WO2003088884A2 - Dynamic infant support and method of operation - Google Patents

Abstract

An infant environmental transition system that provides controlled simulated movements encountered by an infant in an intrauterine environment. The system includes a structure having a plurality of flexures (25, 26) coupled between a base plate (33) and a moving support platform (9). A cam shaft assembly (27) includes a groove (43) that engages a linear (41) follower connected to the moving platform (9) to rotate the platform (9)about a central axis, and a crank and rod connected to the platform (9) reciprocates the platform (9) in a longitudinal direction. Operational control of operating speed of a drive motor (23) is controlled by a microprocessor (10) that responds to sensors to provide operational feedback for speed regulation and safe shutdown under excessive loading or other adverse operating conditions. Pulse width modulation techniques generate sounds and operate visual indicators on a control panel (17).

Description

DYNAMIC INFANT SUPPORT AND METHOD OF OPERATION

Related Cases: [0001] This application claims priority from provisional application Serial

No. , entitled "Dynamic Infant Support and Method of Operation" filed on April 18, 2002 by J. Finkelstein et al, and the subject matter of this application relates to the subject matters of U.S. Patent Nos. 5,037,375 and 5,183,457 and 5,385,153 and 5,845,350 which are incorporated herein in their entireties by this reference.

Field Of The Invention

[0002] This invention relates to a structure that simulates the motion stimuli experienced by an infant in an intrauterine environment.

Background Of The Invention

[0003] Perhaps the most difficult transition a mammal is required to make in its lifetime is the change from the intrauterine environment to the extrauterine environment at birth. Every parameter of the infant's environment changes abruptly. Dramatic shifts in temperature, tactile sensation, audio stimuli, motion, and light are exacerbated by conditions in the hospital delivery room where most women in modern societies give birth. Even the environment in a loving home is alarmingly unfamiliar, and many infants exhibit prolonged crying and sleeplessness which may be related to transitional stress. It is believed that these abrupt changes in the environment tend to intensify the infant's intrauterine to extrauterine transition and may inflict harm which affects the person's emotional and physical response to adaptive or environmental change throughout the remainder of his or her life. Therefore a gradual and effective transition of the infant from the intrauterine environment to the extrauterine environment may have substantial long-term as well as short-term benefits. [0004] An effective transition system should duplicate as closely as conveniently possible the intrauterine conditions perceived by the infant just prior to birth. It should also gradually alter environmental stimuli over time until they correspond to the natural extrauterine environment. [0005] The environmental stimuli vary in complexity and ease of simulation or control. The motion parameter is quite distinctive. Figure la shows the characteristic pelvic displacement patterns of pregnant women while walking. Duplicating the linear and rotational components of these motions requires a sophisticated suspension and motion control and drive system. In addition, cardiovascular and respiration, and digestive sounds associated with intrauterine conditions perceived by an infant prior to birth become familiar stimuli with soothing and calming effect when reproduced to be transmitted to the infant after birth. Accordingly, it is desirable to provide a structure as illustrated in Figure lb including a motion system that is sufficiently small in size and height to support an infant within a confining enclosure, and including devices and controls for simulating motions in varying degrees over intervals of time.

Summary Of The Invention

[0006] The present invention incorporates a motion-oriented environment within a structure that includes a suspension and motion control and drive system which very closely replicates the intrauterine motions that a fetus experiences as the mother is walking. Microprocessor based electronics integrate desired changes in motion and other stimuli to gradually transition the infant from the simulated intrauterine environment to the extrauterine environment, and to provide wide ranging system^; flexibility.

[0007] The present invention produces motion which is quiet, smooth and continuous with high safety and reliability and low maintenance. The electric motor and drive mechanism may be disposed within the structure separated from the control module. In one embodiment, flexure modules that support an articulating main support plate of the structure is actuated by direct mechanical linkage from a motor and drive system that are disposed within and beneath the main support plate of the structure.

Brief Description Of The Drawings

[0008] Figure la is a graph showing the characteristic pelvic motion patterns of pregnant women while walking, which patterns are emulated by the motion parameters of the present invention.

[0009] Figure lb is a perspective view of one product embodiment incorporating the present invention.

[0010] Figures 2a-2d show perspective, bottom, front and end views of a main support plate of the structure and of the subsystems housed within the central portion of the structure of an environmental transition system according to the present invention.

[0011] Figure 3 is an exploded perspective view of the structure and of the operational subsystems according to the present invention.

[0012] Figure 4 is a system diagram of the structure and associated operational control schemes.

[0013] Figures 5a-5d are front, top, perspective and end views of primary flexible supports within the structure.

[0014] Figures 6a-6d are front, top, perspective and end views of secondary flexible supports within the structure. [0015] Figures 7a-7e are top, side, sectional and perspective views of a cam assembly for producing rocking motion of the main support about the central longitudinal axis thereof. [0016] Figure 8a-8d are side, sectional and lower and upper perspective views of a crank assembly for producing translational motion of the main support plate along the central axis thereof.

[0017] Figures 9a-9c are plan and sectional views of a connecting rod with spherical bearings mounted for swiveling in each end thereof.

[0018] Figures 1 Oa-1 Od are top, side and lower and upper perspective views of the drive motor and mounts therefor in the structure of Figure 3. [0019] Figures 11 a- 11 c are side, perspective and sectional views of an idler pulley assembly in the structure of Figure 3. [0020] Figures 12a-12d are top, side, and upper and lower perspective views, of a belt-tightening assembly in the structure of Figure 3. [0021] Figures 13-29 are flow charts illustrating and describing operational controls for the structure of Figure 3.

Detailed Description Of The Invention Overview

[0022] The structure is an electromechanical transition system as illustrated in Figure lb for simulating the prenatal environment. The motion of the support plate 9 simulates the movements, as illustrated in Figure la, and sounds experienced by a fetus while a mother is walking (day mode) and resting (night mode) are simulated and reproduced through a loudspeaker mounted below the support plate 9. The system provides these stimuli to an infant in the extrauterine environment and helps transition the infant from the simulated environment to a natural extrauterine environment over a period of 17 weeks of continuous or lapsed time of operation from initial operation substantially coincident with the infant's birth.

[0023] The system changes the infant's environment by emulating the activities of the mother including varying the rate and volume of the sound pattern (heartbeat) and varying the duration of motion randomly. There are two modes of operation referred to as day and night modes. Day mode of operation establishes a baseline cradle cycle and heart rate frequency higher than that of night mode to thereby simulate the more active mother during the day. In consequence, frequency and volume of the sound pattern increases and decreases, tracking the rocking motion as it slowly accelerates and decelerates. When the system has been started and returns to an inactive (no motion) portion of a cycle, the sound pattern, returns to the baseline previously established. As the infant becomes older and the associated lapsed time of operation of the system increases, the system reduces the simulated stimuli (overall motion and volume) to wean the infant from the structure.

[0024] The system includes an electronic controller 11, external power supply 13 and cradle mechanical assembly 15, as shown in Figure 4. The controller 11 is based upon the P89C51RC2 microcontroller 10 which is responsible for a variety of tasks including controlling motion speed of the cradle in response to user input data via keypad 17, updating the displays 19, and generating the sounds. The controller interfaces with a loudspeaker 21 and motor 23 mounted in the mechanical assembly, as illustrated in Figure 3, via an interconnecting wire harness. Cradle and motor speed feedback signals are also sent back to the controller 10, as later described herein. The cradle mechanical assembly includes a moving top support plate 9, as illustrated in Figures lb, 2a- 2d, suspended by metal spring flexures 25,26 as illustrated in Figures 5a-5d and 6a-6d. The flexures 25,26 are actuated through cam 27 and crank 29 mechanisms that are driven by a pulley-sprocket-belt drive mechanism as shown in Figures 3, 7a-7e, 8a-8d, 9a-9c, 1 la-1 lc, and 12a-12d, driven by the motor 23 shown in Figures 10a- lOd to produce the cyclic motions. The load placed on the support plate 9 includes the infant in a confining container such as a bassinette 31 and is transmitted through the flexures and support bearings to the base plate 33. The resilient, flexible flexures 25,26 are rotationally supported on shafts between bearing blocks 35 for control of translation and rotational roll motions that require only nominal torque from the motor 23.

[0025] The user selects the desired simulated environmental parameters from the 'weeks after birth' input on the keypad 7 of the control panel. Increasing the infant age (weeks after birth) reduces the overall system motion time and decreases the heartbeat volume. Selecting the night mode of operation reduces the nominal number of cradle cycles per minute from 15 to 10 and decreases the sound volume and heart rate for the timed duration of the right mode. [0026] Smooth, quiet, and random cyclic motion is implemented using both electrical and mechanical components. The drive mechanism includes a Brushless DC (BLDC) motor 23, as shown in Figures 3, 10a- lOd, which increases system reliability and decreases motor noise. The BLDC motor 23 supplies the controller 10 with rotational feedback signals from Hall-effect magnetic sensors assembled within the motor 23, and these feedback signals allow the controller to maintain and control speed more accurately and with a higher update rate for better cradle performance and better error handling capabilities.

[0027] A commercially-available eight-pole, brushless DC (BLDC) motor 23 actuates the top support plate 9 through the cyclic motions via an actuating mechanism 15, as shown in exploded perspective and detailed Figures 3, 7-12. The motor 23 contains integral Hall-effect sensors that operate with controller 10 to control commutation of the electric fields and operates from a +15Vdc supply 13. The keypad inputs and motor Hall-effect outputs interface with the microcontroller 10 to establish closed-loop control of the motor speed, as illustrated in the flow charts of the control routines shown in Figures 13-23, at the settings determined with respect to the infant-age data entered via the keypad 17. The microcontroller 10 produces a pulse- width-modulated (PWM) signals 81, 83 that runs at 32 kHz and variable duty cycle which is supplied to the motor 23. Increasing the PWM duty cycle, increases the motor speed, and the motor speed is indicated by the frequency of the motor Hall-effect output signals. For every revolution of the motor shaft, four Hall-effect pulses are produced (one pulse per 90 degrees rotation) which are used as feedback signals for controlling the cradle speed. [0028] The cradle speed is calculated from the motor speed by a fixed scale value based upon the fact that the drive mechanism does not slip. With a drive ratio between the motor pulley 73 and cam assembly 27 of approximately 46.5: 1 and four Hall-effect pulses occurring for every revolution of the motor shaft, a speed update occurs approximately every 21 milliseconds at a nominal speed of 15 cycles/min. This allows for relatively quick control loop response to any error between the measured speed and target speed for proportionally adjusting the PWM signals supplied to motor 23. The PWM (32 kHz) signal supplied to the motor 23 is updated every 50 ms with a variation in the pulse width proportional to the speed error. [0029] Hall-effect input signals are also derived from the actuating cam 27 and are used to detect additional motion errors as illustrated in the routines shown in Figures 24,25, and are also used in conjunction with the motor Hall- effect input signals to detect operational and manufacturing motion errors. These errors are detected by counting the accumulated number of motor Hall-effect pulses occurring for every cam Hall-effect pulse. The expected number of motor Hall-effect pulses 87 should be within an acceptable range. An accumulated pulse count outside this limit is an error indicative of belt slippage (too many motor pulses) or incorrectly manufactured mechanical drive. [0030] The upper support plate 9 is supported by a suspension system including two flexure assemblies 25,26 mounted near opposite ends of the support plate 9, as shown in Figures 2a-2d. The primary flexure assembly 25 is mounted next to the cam 27 of Figures 7a-7e and comprises two spring flexures of spring steel or other flexible, resilient material (such as sheet fiberglass), as shown in Figures 5a-5d. The two springs are mounted back-to-back and are held together by inner 37 and outer 39 spring blocks, which captivate the flexures and which are mounted for rotation on shafts between support brackets 35 that are attached to the base plate 33. A cam follower 41 as shown in Figure 5b is attached to the inner spring block 37 on this assembly and rides in a groove 43 in cam 27, as shown in Figures 7a-7e. As the cam follower 41 rides up and down in the groove 43 of the vertically-rotating cam 27, a rocking motion of the support plate 9 is produced about its central axis. This spring flexure assembly provides vertical rigidity and increased resistance to rotational forces exerted on the flexure under load. The ends of the spring flexures are attached to the sides of the support plate 9 by four mounting blocks 45-47.

[0031] The secondary flexure 26 includes a single spring flexure, as shown in Figures 6a-6d. This assembly is mounted on the opposite end of the support plate 9 via two mounting blocks 48,49. Infant loading placed on the top support plate 9 is carried by the flexures 25,26 which require minimal driving torque to create longitudinal flexure for quiet, smooth, low-maintenance cyclic flexure motion along the central axis of the support plate 9.

[0032] Torsional stiffness is provided by the spring flexures 25,26 that are rigidly attached to the support plate 9, as shown in Figures 2a-2d, that serves as the platform for the infant container 31 such as a bassinet. Surrounding skirts may be attached to the support plate to enclose the moving mechanical components and restrict access to exposed moving parts in the structure illustrated in Figure 3.

[0033] The longitudinal motion of the support plate 9 is generated by a connecting rod 51 shown in Figures 9a-9c that links the support plate 9 and the end of a crank arm 29 mounted to a crankshaft assembly 53. The crank arm 29 rotates in the same generally horizontal plane as the support plate 9 and is attached thereto at one end of the connecting rod 51 by a ball-and-socket union 55. The other end of the rod 51 includes a ball bearing for rotation about the crank pin on crank arm 29. One or both ends of the connecting rod 51 pivot around the crank and/or around the attachment to the support plate 9 to accommodate the rocking motion. . The connecting rod 51 reciprocates in the longitudinal direction relative to the support plate at two strokes (forward- backward) per side-side rocking motion of one cradle cycle. The ball bearing and ball-and-socket joints 55,57 on the connecting rod 51 provide quiet, low- maintenance operation with minimal wear and frictional losses. [0034] The cam assembly 27 illustrated in Figures 7a-7e is driven by a toothed belt to eliminate noise and vibration commonly associated with gear drives. [0035] The crank assembly 27 of Figures 8a-8d drives the cam assembly 27 of Figures 7a-7e via a toothed belt to eliminate slippage and spur gear noise. A ball-bearing idler 59 and tensioner as illustrated in Figures 12a- 12d is placed between the crank pulley and the cam pully to keep tension on the belt. An intermediate idler 61 in the drive assembly includes a large pulley 63 attached to a hub that is fastened to the intermediate shaft 65, as shown in Figures 1 la-1 lc, for belt-driven rotation by motor 23. The shaft runs through an intermediate bearing housing 67, which mounts to the bearing-supporting base plate 69. Ball bearings inside the bearing housing allow the shaft to rotate smoothly and quietly. A sprocketed pulley 71 is attached on the upper end of the shaft to accommodate the toothed belt that rotates the crank assembly 53. Tension on both belts can be adjusted by loosening the four bolts securing the bearing support plate 69 to the base plate¹33, adjusting the tension appropriately, then re- tightening the bolts. The micro- V belt on pulley 63 increases the frictional coefficient between the belt and pulley and provides excellent resistance to slipping under maximum load.

[0036] The drive motor 23 shown in Figures 10a- lOd is an eight-pole, brushless DC motor with integral drive electronics. The motor is mounted with the motor shaft 73 pointing downwardly. A micro-V pulley 73 is attached to the end of the motor shaft with a roll pin and is aligned in the same plane as the large pulley 63 of the intermediate idler. The brushless motor 23 has a longer mean- time-before failure (MTBF) rating and runs quieter due to the absence of brushes.

[0037] Operational firmware resides in FLASH memory in the P89C51RC2 microcontroller 10 shown in Figure 4. The firmware code is written in the C- programming language to provide portability across multiple hardware platforms. The code is primarily responsible for reading and processing the user inputs (from keypad 17), controlling the cradle speed, and generating the intrauterine heartbeat sound played through the loudspeaker 21, as shown in Figure 3. Selected ones of these operations including self-diagnostics and error logging to non-volatile memory, are illustrated and described in the flow charts of Figures 13-29. Specifically, when the cradle is first turned on, the controller performs initialization sequences. If the key sequence for audio gain adjustment is selected on power up, the user can adjust the audio volume by increasing or decreasing the gain.

[0038] After the initialization sequences are completed, the controller 10 checks if the cradle application or the test mode application should be entered. In test mode, the controller 10 processes commands from a host PC (not shown) across an asynchronous serial communication link such as RS 232 link 75. This mode is used for manufacturing and testing purposes.

[0039] Upon entry of the cradle application, the unit performs a self- diagnostics check of the integrity of the power supply voltages, the audio drive circuitry, the internal FLASH checksum and the failsafe motor circuitry. If an error is detected, the appropriate error number is displayed on a 7-segment LED display 19 and logged to non-volatile memory (EEPROM).

[0040] After self-diagnostics are completed, the controller 10 proceeds with loading parameters from the non-volatile memory (EEPROM). Parameters are stored and saved to non-volatile memory as either modifiable or fixed. Critical modifiable parameters are stored as three separate copies to EEPROM with each copy containing a checksum. This ensures the previous values can be restored in the event power is lost during a parameter write/save cycle. The critical modifiable parameters are infant age, audio gain (loud speaker volume) and current cradle cycle count. [0041] The cradle application begins toggling the FAILSAFE signal in the background enabling the +15V supply for connection to the motor. When the START button is pressed, the electronic and mechanical cradle assemblies ramp up to the final target speed (nominal 10 cycles/min NIGHT MODE or 15 cycles/min DAY MODE). The heart rate and volume also increase in correlation with the ramp up to target speed.

[0042] The controller 10 provides a PWM output to the integral drive electronics for the motor 23 to set the motor speed. On startup, an initial, high startup value of PWM duty cycle is used to ensure that the motor 23 starts under worst-case load conditions. Motor speed feedback is provided to the controller in response to the motor Hall-effect outputs that are produced at the rate of four Hall-effect pulses per revolution of the motor shaft 73. The controller 10 captures the elapsed time between each pulse using the capture/compare unit peripheral on the microcontroller (I^>89C51RC2). On every falling edge, an interrupt is generated capturing the elapsed time between successive Hall-effect pulse edges. This elapsed time is used to calculate the actual cradle speed based upon the mechanical fixed drive ratio between the motor 23 and the cam assembly 27. The measured speed is compared with the target motor speed and the speed error is used to adjust the PWM drive signal to the motor 23 proportionally in a gradual, ramping mode. [0043] Another Hall-effect signal input to the controller 10 measures the cradle speed based upon a magnet 77 mounted on the cam assembly 27. This input generates one pulse per revolution of the cam 27, or one pulse per cradle cycle. The input is polled at the system tick time interrupt rate (every 4ms). A falling edge on this input indicates that a Hall-signal interrupt from the cam 27 has occurred and the current cycle count is incremented. The current cycle count is saved to EEPROM every 16 cycles to prolong the life of the EEPROM. This input is not used to control the cradle speed but is used to detect cradle operating and manufacturing errors such as belt slippage and incorrectly sized pulleys/sprockets.

[0044] When the STOP button is depressed, if the cradle is already in motion, the controller decelerates gradually from the current target speed to a safe stopping speed of about 7 cycles/min, and also decreases the heart rate and volume. When the cradle has reached the safe stop speed, the controller 10 responds to the next Hall-effect signal from the cam 27. When this signal is detected, the controller 10 turns off the motor 23. This assures that the support plate 9 stops and starts in a substantially horizontal plane parallel to the base plate 33. [0045] Depressing the INCREMENT AGE or DECREMENT AGE buttons on keypad 17 adjusts the infant age in increments or decrements of 1 week ranging from 1 week to 17 weeks old. The 7-segment display 19 updates accordingly, and the new age is saved to EEPROM. Increasing age decreases the sound volume and the overall time the cradle is in motion during random intervals of movement, based upon its programmed operational characteristics. [0046] LED displays are dimmed in NIGHT MODE by effectively decreasing the amount of time the LEDs are turned on. This is accomplished by driving the display segments with PW signals, and dimming of the display is accomplished by decreasing the PWM duty cycle of signal supplied to the LED display. [0047] The 7-segment display 19 and individual LED displays are multiplexed to display or announce the typical display messages (e.g., START, STOP, DAY, and NIGHT). The multiplexing of the LED displays occurs every 4ms at the system tick interrupt rate. The START, STOP, NIGHT, and DAY LED displays are updated for three consecutive 4ms intervals for latent display, followed by an update of the 7-segment display for two consecutive cycles. The multiplexing repeats on the following system tick.

[0048] Sound generation is accomplished by stepping through a digitized table of stored samples of heartbeat (or other sounds) as detected within the uterus. A timer interrupt is generated periodically. Each time an interrupt occurs, a value from the table is read, scaled by the effective audio gain and used to generate a PWM output running at 32khz. The timer interrupt rate sets the heart beat frequency, and the audio gain sets the volume. A PWM output from the microcontroller 10 for sound generation is low-pass filtered to produce the heartbeat signal supplied to the loud- speaker 21.

[0049] Since the P89C51RC2 microcontroller 10 does not have an integral analog-to-digital converter (ADC), analog-to-digital conversion is accomplished in accordance with one embodiment of the present invention by feeding an analog signal to be sampled into an inverting input of a comparator. A 32khz PWM signal beginning at 100% (OxFF) duty cycle is supplied to the non- inverting comparator input. The PWM value is decremented by 0.4% (0x01) every 4 ms until the comparator output goes low, at which time the PWM value that caused the comparator output to go low is the digitized analog value. Analog channel multiplexing, settling delays, and sampling are performed at the system tick time interrupt.

[0050] The system power supply voltage levels are periodically checked to set an error flag if a supply is out of tolerance.

User Input Processing [0051] The reading and debouncing of the user input switches on keypad 17 occur every 20ms at the system tick timer interrupt. The user input processing allows for multi-key sequences to be recorded. These multi-key operations are generally reserved for atypical system operations such as adjusting audio gain. A repeat key operation is also provided for those key operations requiring a 'repeat' action.

[0052] A secondary task of the cradle application is performing error handling. Errors are defined lowest (0) to highest priority level (3) with unmaskable errors set to level 3. An error mask stored in EEPROM disables or enables error handling at levels 0 through 3. For example, setting the error mask to 2 enables handling of errors of level 2 and higher. Special bits in the field and each individual error type indicate the action to be taken if an error event occurs. If the error type field indicates the error should be saved to EEPROM, the posted error is saved as a bit mask allowing multiple errors to be logged. The error log in EEPROM is reset when the error log is displayed.

Claims

We claim:

1. Apparatus for controlling operations of an infant-oriented environment, comprising: an infant-supporting platform mounted for translational and rotational roll movements; a cam structure rotatably mounted relative to the platform and coupled thereto for establishing translational and rotational roll movements thereof in response to rotation of the cam structure; a drive motor coupled to rotate the cam structure at a selected rotational reduction ratio relative to rotation of the drive motor; a plurality of sensors disposed with respect to the drive motor and cam structure for producing signals indicative of angular rotational positions thereof; and a controller communicating with the sensors and coupled to actuate the drive motor at a selected rotational speed in response to signals received from the plurality of sensors for producing cyclic translational and rotational roll movements of the platform.

2. Apparatus according to claim 1 in which the controller actuates the drive motor to attain the selected rotational speed over an interval during which the rate of change of rotational speed is non-zero.

3. Apparatus according to claim 1 for controlling operations of the infant-oriented environment from its initial operation corresponding substantially to the birth of the infant, and in which the controller alters the selected rotational speed in response to one of time of day and total lapsed time from initial operation.

4. Apparatus according to claim 1 in which the controller actuates the drive motor to attain the selected rotational speed over an interval of acceleration.

5. Apparatus according to claim 2 in which the controller actuates the drive motor to achieve the selected rotational speed over an interval of deceleration.

6. Apparatus according to claim 5 in which the selected rotational speed is a non-zero value to which the rotational speed decelerates; and the controller responds to a signal from the cam structure for terminating actuation of the drive motor during the non-zero value of rotational speed to position the platform in a selected translational and rotational roll static attitude.

7. Apparatus as in claim 1 in which the controller responds to sensor signals from the drive motor and from the cam structure to produce an output error indication in response to a variation about the selected reduction ratio.

8. Apparatus including a motor-driven movable platform for an infant- oriented environment, the controller comprising: a controllable switch connected to the drive motor for selectively applying power thereto from a source; a processor coupled to the switch for selectively turning on and turning off power from the source applied to the motor at a rapid rate under pulse-width modulation control to alter speed of the motor in response to modulation of the pulse width; a coupling structure connecting the drive motor to the platform for moving the platform through a predetermined cycle of motion in response to rotation of the drive motor; and a sensor disposed with respect to the coupling structure to apply a control signal to the processor in response to a cycle of motion, said processor responding to the time interval between control signals applied thereto from the sensor for comparison with the speed of the drive motor as an indicator of any mechanical slippage between the drive motor and coupling structure.

9. Apparatus according to claim 8 in which the processor is operable to modulate the pulse width of power applied to the drive motor through said switch for operating the drive motor at an intermediate speed, and to turn off power to the drive motor operating at the intermediate speed at an orientation of the platform for which the sensor is aligned at a selected position in the cycle of motion.

10. Apparatus according to claim 8 in which the processor turns off power to the drive motor under conditions during cycles of motion for which the control signals recur at time intervals longer than one interval limit, or shorter than another interval limit for safe shutdown of power applied to the drive motor during operating speeds thereof not within speed limited corresponding to said one and said another interval limits.

11. Apparatus according to claim 8 in which the processor establishes recurring intervals of power supplied to the drive motor that vary in one of duration and spacing in time in response to total lapsed time from initial operation.

12. Apparatus according to claim 8 in which the processor establishes recurring intervals of power supplied to the drive motor that vary in one of duration and spacing in time in response to the time of day.

13. A method for controlling movements of an infant-supporting platform through motor-driven cycles of combined translational and rotational roll movements, the method comprising: forming signals indicative of drive motor position and platform position during a cycle of the movements thereof; selectively applying power to the drive motor in response to signals therefrom for operating the drive motor at a selected speed; and terminating application of power to the drive motor in response to signal from the platform indicative of a selected position thereof for positioning the platform at a desired stable attitude within a cycle of the combined movements thereof.

14. The method according to claim 13 in which power is applied to the drive motor for operation thereof at an intermediate speed prior to terminating application of power to the drive motor.

15. The method according to claim 13 in which power is selectively applied to the drive motor during an interval in which the rate of change of speed of the drive motor is non-zero.

16. The method according to claim 15 in which a succession of intervals are altered in duration and spacing in time in response to one of the time of day and the total elapsed time from initial operation.

17. The method according to claim 13 in which power is randomly applied to the drive motor during intervals randomly determined in response to the time of day.

18. The method according to claim 13 including forming an error indication in response to the difference in recurrence rates of signals indicative of drive motor positions and indicative of platform positions varying from a selected ratio.

19. The method according to claim 13 in which selectively applying power includes supplying modulated pulses of power to the drive motor to increase speed in relation to pulses having one of increased width and increased amplitude.

20. Apparatus for supporting an' infant-oriented environment for combined rotational roll and translational movement, the apparatus comprising: a platform having upper and lower surfaces and descending sides oriented longitudinally along the platform; a plurality of flexures disposed near the lower surface of the platform extending between the sides thereof, each flexure including a sheet of flexible, resilient material oriented substantially normally to the lower surface and including attachments to the sides of the platform at selected locations along the length thereof; one of the plurality of flexures being attached at opposite ends thereof to corresponding sides of the platform near one end thereof, and another of the plurality of flexures being attached at opposite ends thereof to corresponding sides of the platform near an end thereof opposite the one end; each of said plurality of flexures being resiliently flexible to translational movement of the sides in alignment with a longitudinal axis thereof relative to a central region of each flexure, and rigid to force exerted substantially normal to the upper surface of the platform; and support structures disposed in the central regions of each of the plurality of flexures to mount the flexures for rotational movement thereof about an axis aligned with the central regions.

21. Apparatus according to claim 20 in which each of the plurality of flexures includes end portions angled relative to and integral with a lateral portion that extends substantially between the sides.

22. Apparatus according to claim 21 in which said another of the flexures attached to the sides near the ends thereof opposite said one end comprises at least one flexure disposed between sides with the corresponding end portions attached to each side, and with the central region thereof aligned along said axis.

23. Apparatus according to claim 22 in which said another of the flexures comprises a pair of said plurality of flexures disposed in contiguous back-to-back orientation with corresponding end portions extending in opposite directions as attached to each side.

24. Apparatus according to claim 22 in which said another of the flexures includes a cam follower arm attached thereto extending from the central region substantially normally to the axis for exerting rotational torque on said another of the flexures about the axis.

25. Apparatus according to claim 20 in which the material is flexible and resilient and the sides of the platform are rigidly attached to end portions of the flexures.

26. Apparatus according to claim 21 in which attachments of the end portions of the flexures to corresponding sides of the platform are displaced from the lateral portion to permit flexure of an end portion relative to a lateral portion to compensate for elongation of a flexure between attachments of end portions thereof to corresponding sides of the platform in response to longitudinal movement thereof in alignment with the axis.

27. Apparatus according to claim 20 in which the support structures include a rigid element having an arcuate face contiguously attached to the flexure in the central region thereof to permit migrating contact of the flexure along the arcuate face.