Patent Publication Number: US-6705917-B2

Title: Self-phase synchronized walking and turning quadruped apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims benefit of U.S. Provisional Application No. 60/255,974, filed Dec. 15, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to quadruped walking platforms that achieve synchronized walking and turning and, more particularly, to quadruped walking platforms that achieve self-phase synchronized walking and turning by using a damper mechanism and a phase lock bar. 
     2. Description of the Related Art 
     There are numerous examples in the prior art of walking devices that use a single motor that is coupled to a single crank shaft which in turn drives the two rear limbs that are also connected to two front limbs. The crank shaft typically has two crank throws that have a phase differential of 180 degrees between them with each of the throws rotatably connected to the corresponding rear limb. As a result, the motor causes one side of legs to thrust while the other side is planting, thereby mimicking the walking of a four-legged animal. 
     These devices can walk in a forward manner when the motor is rotating in that direction. In the alternative, these devices can walk in a reverse direction when the motor is reversed. Although these prior art devices can walk effectively, they are still unsatisfactory for at least two reasons. One problem with these devices is that they lack the ability to alter the phase differential between the left and right sets of limbs. Moreover they may not be able to restore the original phase differential once it has been disturbed. Therefore, these devices lack the ability to turn and to truly mimic the walking motion of a four-legged animal. Likewise, these devices lack the ability to turn on axis. As a result of these deficiencies, these devices cannot avoid obstacles or seek out objects in their environment. 
     A prior solution for this problem is the use of multiple motors, (e.g., twelve or more motors), that are under servo control from a computer. In these devices, the servo/computer generates the phase and sequence that the motors on the limbs must achieve to walk successfully. This solution can be cost prohibitive because of the need for many motors, a servo, and a computer as well as its inherent complexity. Accordingly, there exists an unfulfilled need for a quadruped apparatus that can turn both conventionally and on axis in a way that is more cost effective than any method taught by the prior art. 
     A second problem with these prior art devices is that they do not interact with their environment or make other non-ambulatory movements in a manner that resembles animals. Their inability to turn contributes to this problem because they can not interact with their environment because they are unable to alter their course in response to stimuli. In addition, these platforms frequently have only one motor that powers the walking motion of the devices. Therefore, they lack the source of power to create non-ambulatory movements such as moving their head toward a movement taking place around them, rendering them unlike animals. This can be disadvantageous in the robotic and toy fields where the goal is to have a device that is as similar to animals as possible. Accordingly, there exists a further need for a quadruped apparatus that can interact with its environment by turning or making non-ambulatory responses to stimuli. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a walking apparatus is provided that includes the ability to turn, both conventionally and on axis, and to respond to stimuli in its environment. This is achieved by providing a rapid and effective way to disturb and restore lateral phase differential from the limbs on one side of the apparatus to the other. The result is an apparatus that can turn in a conventional manner when both sets of limbs are moving in the same direction while also being able to turn on axis when both sets of limbs are moving in opposite directions. In addition, the invention provides a means for simple interface and control by a computerized apparatus so that it can process input signals from its environment, choose an appropriate response, and then execute that response. These features render the apparatus more like animals than those devices found in the prior art. Consequently, these apparati can be used in a wide variety of applications ranging from toys to advertising, to robotics, and to remote control devices. 
     One embodiment of the invention includes a first motor that is attached to the apparatus and is in communication with a first limb. This embodiment also includes a second motor attached to the apparatus that is independent from the first motor. It is in communication with a second limb that is capable of moving at a different rate than the first limb. Next, at least one damper mechanism is interposed between the first limb and the second limb, or other movable components mechanically linked thereto, which typically have a phase differential of 180 degrees between them, such that the damper mechanism will supply force to resist any change in the phase differential between these limbs. This damper mechanism may take the form of a simple torsion spring, but may comprise of other devices that are readily apparent to those skilled in the art such as brakes, clutches, compression springs, piston assemblies, etc. Thus, the phase differential will be maintained unless some force overcomes the force exerted by the damper mechanism. 
     The apparatus may be powered electrically, chemically, by solar power, etc. to cause the first and second motors to rotate their respective drive shafts. This energy is then mechanically transmitted to the first and second limbs causing them to make a stepping motion. Since the motors and limbs are independent from each other, a regulator may be used in conjunction with these motors so that their speed may be altered with respect to each other, thereby disturbing the phase differential originally established between them by overcoming the force exerted by the damper mechanism. The end result is that one limb will move faster than the other, causing the apparatus to turn in a prescribed radius. Once the force controlled by the regulator is removed from the motor, the force exerted by the damper mechanism will restore the original phase differential until both the first and second limbs are moving at the same rate causing the apparatus to walk in a straight line. Since this embodiment has only two legs, it may also have two wheels so that the apparatus will more closely resemble a quadrupedal animal. As can be seen, this invention provides a more efficient, simple, and cost effective way of providing an apparatus that can turn to seek out an object such as a ball or avoid an obstruction such as a mountain or a chasm than prior art devices. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a perspective view of a quadrupedal and fully canine apparatus that can walk toward objects using an infrared sensor; 
     FIG. 1B is a perspective view of the quadrupedal apparatus showing its main ambulatory components; 
     FIG. 1C is a perspective view of the quadrupedal, canine walking apparatus showing how the damper mechanism works; 
     FIGS. 1D and 1E illustrate the damper mechanism operation with phase regulation using compression springs; 
     FIG. 2A is left elevational view of the apparatus as it is thrusting forward during its walking sequence; 
     FIG. 2B is a rear elevational view of the apparatus as it is thrusting forward during its walking sequence; 
     FIG. 3A is a left elevational view of the apparatus as it is transferring opposite during its walking sequence; 
     FIG. 3B is a rear elevational view of the apparatus as it is transferring opposite during its walking sequence; 
     FIG. 4A is a left elevational view of the apparatus as it is setting its front leg while walking; 
     FIG. 4B is a rear elevational view of the apparatus as it is setting its front leg while walking; 
     FIG. 5A is a left elevational view of the apparatus as it is transferring same during the walking sequence; 
     FIG. 5B is a rear elevational view of the apparatus as it is transferring same during the walking sequence; 
     FIG. 6A is a walking motion chart showing the phase and sequence of the legs during its walking sequence; 
     FIG. 6B is a walking motion chart showing the phase and sequence of the legs during its walking sequence; 
     FIG. 6C shows the apparatus maintaining its center of balance within its stability envelope while walking; 
     FIG. 6D shows the apparatus&#39; ability to walk forward, reverse, and to turn conventionally; 
     FIG. 6E is a rear view of the apparatus as it turns on axis; 
     FIG. 6F is a walking motion chart showing the phase and sequence of the legs while the apparatus is turning on axis; 
     FIG. 6G shows the apparatus maintaining its center of balance withing its stability envelope while walking; 
     FIG. 6H shows the apparatus&#39; ability to turn on its axis; 
     FIG. 7A is a perspective view of the apparatus showing its third motor which causes non-ambulatory movement; 
     FIG. 7B is a perspective view of the apparatus showing the location of its batteries; 
     FIG. 7C is a perspective view of interactive components of the apparatus including pet switches, emitter LEDS, sensors, microphones, and a speaker; 
     FIG. 7D is a perspective view of the apparatus showing its drive train assemblies; 
     FIG. 8A is a left side elevational view of the apparatus; 
     FIG. 8B is a front elevational view of the apparatus; 
     FIG. 8C is left cross-sectional view of the apparatus; 
     FIG. 8D is a front cross-sectional view of the apparatus; 
     FIG. 8E is a left perspective view of the apparatus as it sits; 
     FIG. 8F is a front perspective view of the apparatus as it sits; 
     FIG. 8G is a left perspective view of the apparatus as it speaks and wags its tail; 
     FIG. 8H is a front perspective view of the apparatus as it speaks and wags its tail; 
     FIG. 9 is a high level flow chart showing how the apparatus responds to stimuli in its environment; 
     FIG. 10 is a system layout showing how the interactive components of the apparatus are connected to the system CPU; 
     FIG. 11 shows how the sensors, output components, mechanical components, and software work together to allow the apparatus to interact with its environment; 
     FIG. 12 shows a wiring schematic of the standard H bridge circuits that control the three motors; and 
     FIG. 13 shows a wiring schematic for the entire apparatus. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1A-8H, the preferred embodiment of the present invention is one that is quadrupedal and is fully canine. This embodiment includes a first motor  20  within the rear portion of the apparatus that has a drive shaft  22  extending therefrom. Fixedly attached to the drive shaft  22  of the first motor is the first gear  24  of the first gear train. This gear meshes with a second gear  26  of the first gear train that is larger and is mechanically coupled to the first crank shaft  28 . The difference of the relative sizes of these gears increases the torque supplied by the motor to the limbs in order to improve its ability to drive the apparatus. Of course, multiple gears may also be interposed between the first gear  24  and second gear  26  of the first gear train in order to achieve the exact torque amplification that is desired. Next, the first crank shaft  28  is rotatably and eccentrically attached to the first bell crank  30 . Anywhere between the first bell crank  30  and the first motor  20 , there may be a first clutch  32  positioned such that if one of the legs mechanically linked to the first motor  20  becomes entangled and unable to move, then the first motor  20  will be disengaged from the limbs, thereby avoiding damage to the first motor  20 . The lower portion of the first bell crank  30  serves as a first rear limb while its other end is rotatably attached to the first front limb  36 . The first front limb  36  is also rotatably attached to the apparatus with the axis of rotation of that attachment being eccentric to the axis of rotation of the attachment to the first bell crank  30 . 
     Consequently, the motion of the first motor  20  is communicated through these components and results in a stepping motion of the first front limb  36  as it swings back and forth. It is readily apparent to those skilled in the art that this communication could also be accomplished through the use of belts, chains, linkages, etc. The first rear limb  34  makes tiny circles which causes it to also make a stepping motion at the same time the first front limb  36  is moving because dorsal phase differential is maintained by the mechanical coupling of the first front limb  36  to the first rear limb  34 . The radius of this circle is equal to the eccentricity  38  of its rotatable attachment to the first bell crank  30  and determines the height of the step  40  for the apparatus. 
     The present preferred embodiment also includes a second motor  42 , independent of the first motor  20 , that is within the rear portion of the apparatus and has a drive shaft  44  extending therefrom. Fixedly attached to the drive shaft  44  of the second motor is the first gear  46  of the second gear train. This gear meshes with a second gear  48  of the second gear train that is larger and is mechanically coupled to the second crank shaft  50  which can be oriented to any phase with respect to the first crank shaft  28 . As mentioned above, the difference of the relative sizes of these gears increases the torque supplied by the motor to the limbs in order to improve its ability to drive the apparatus. Again, multiple gears may also be interposed between the first gear  46  and second gear  48  of the second gear train in order to achieve the exact torque amplification that is desired. Next, the second crank shaft  50  is rotatably and eccentrically attached to the second bell crank  52 . Anywhere between the second bell crank  52  and the second motor  42 , there may be a second clutch  54  positioned such that if one of the legs mechanically linked to the second motor  42  becomes entangled and unable to move, then the second motor  42  will be disengaged from the limbs, thereby avoiding damage to the second motor  42 . The lower portion of the second bell crank  52  serves as a second rear limb  56  while its other end is rotatably attached to the second front limb  58 . The second front limb  58  is also rotatably attached to the apparatus with its axis of rotation being eccentric to the axis of rotation of the attachment to the second bell crank  52 . 
     As a result, the motion of the second motor  42  is communicated through these components, independent of the motion of the first front  36  and first rear  34  limbs and with a phase differential, and results in a stepping motion of the second front limb  58  as it swings back and forth. As noted above, this communication could also be accomplished through the use of belts, chains, linkages, etc. The second rear limb  56  makes tiny circles which causes it to also make a stepping motion at the same time the second front limb  58  is moving because dorsal phase differential is maintained by the mechanical coupling of the second front limb  58  to the second rear limb  56 . The radius of this circle is equal to the eccentricity  38  of its rotatable attachment to the first bell crank  30  and determines the height of the step  40  for the apparatus. Preferably, the components and dimensions of the left side of the apparatus match those of the right side, thereby ensuring symmetry which helps the apparatus to maintain balance and closely resemble a canine while it walks. 
     An advantageous feature of the preferred embodiment is a phase lock bar  60  that is rotatably attached to the apparatus at a pivot point  62  near the top, rear, and center of the apparatus. Preferably, the length of the phase lock bar is symmetrical about this pivot point  62  such that its first end  64  slightly overhangs the first bell crank  30  while its second end  66  slightly overhangs the second bell crank  52 . Interposed between the first end  64  of the phase lock bar and the first bell crank  30  is a first damper mechanism  68  which may take the form of a first compression spring  70 . Symmetrically, a second damper mechanism  72  including a second compression spring  74  may also be interposed between the second end  66  of the phase lock bar and the second bell crank  52 . It is preferred to use two springs so that the length of the springs and their spring constants may be optimized so when phase is achieved they are relaxed and at maximum compression when phase slips beyond compensation. This modality for the springs is true for all states of forward, reverse, turn on radius and turn on axis. 
     The resulting structure is capable of maintaining a normal 180 degree phase differential between the left and right sides for forward and reverse. The resulting structure is also capable of maintaining a nominal sliding phase differential between the left and right sides for radius turns. Finally, the resulting structure is capable of maintaining a 90 degree counter phase differential between the left and right sides for axial turns. This structure of the apparatus also continually compensates against minor variances caused by the motors or the surroundings binding or dragging on the apparatus. This is achieved by way of the phase lock bar  60  which acts as an vertical differential oscillating regulator or a “see-saw” as it follows the vertical vector motion of the bell cranks up and down relative to each other. The phase bar  60 , equally distribute retarding forces via the springs  70  and  74 , to both motors forcing them to constantly seek the nominal phase for the particular regime of walking. If the timing is upset by forcibly increasing the speed of the first motor  20  or second motor  42  by way of the first regulator  76  or second regulator  78 , then the first  70  and second  74  compression springs begin to compress and exert force on the first  30  and second  52  bell cranks, retarding or dampening any disturbing forces, until phase differential has been restored (see FIG.  1 C). 
     When walking forward, the motors are out of phase at 180 degrees, the spring retarding force is essentially zero. At a 90 degree change of phase, the spring retarding force rises to that equal to walking friction. At 0 degrees phase differential, the spring force is at its highest at 4 times walking friction. This phase to retardation dampening force ratio is further enhanced by the fact that the lateral sequence of walking, left and right sides, is sensitive to the phase angle of the bell cranks. At plus or minus 20 degrees from nominal phase differential no effective walking motion, i.e., relative forward or turning motions will take place. The net result is as phase is lost relative motion is lost until phase is restored. This means that when the apparatus is disturbed, it will continually apply more torque to automatically correct phase despite the resisting force. This damping force will continue until zero phase or highest torque is achieved. If this fails to achieve correction the cycle repeats. When phase is restored normal motion will be restored. Without the phase lock bar  60 , this apparatus is incapable of coherent motion and would simply oscillate in place with no relative motion. As can be seen, this invention thereby provides an apparatus with a unique, novel, and non-obvious method of walking and turning than found in the prior art. 
     FIGS. 2A and 2B show the position of the first rear limb  34 , the first front limb  36 , and the second rear limb  56  during the initial phase of the walking sequence of the apparatus. Initially, the rear limbs are planted flatly on the ground while the first front limb  36  is tilted slightly forward. Since the lateral phase differential is still at 180 degrees, neither the first compression spring  70  nor the second compression spring  74  are compressed. It should be noted that FIG. 2A shows only the position of the first front limb  36  and first rear limb  34  while the second front limb  58  and second rear limb  56  have been omitted for the sake of clarity. 
     FIGS. 3A and 3B show the second phase of the walking sequence of the apparatus. As can be seen, the first rear limb  34  begins to rise as the second rear limb  52  pushes down on the ground. Hence, the second rear limb makes a step with a height  40  equal to the eccentricity  38  of the connection of the first bell crank  30  to the first crank shaft  28 . At the same time, the first front limb  36  swivels until it is leaning slightly backwards. Once again, FIG. 2B depicts that the lateral phase differential has been maintained at 180 degrees, resulting in no compression of either the first compression spring  70  or the second compression spring  74 . 
     Turning to FIGS. 4A and 4B, it is clear that the first rear limb  34  is once more firmly and flatly planted upon the ground. Due to the rotation of the first bell crank  30 , the first front limb  36  is tilted toward the rear at the most severe angle possible during the walking sequence of the apparatus while at the same time the position of the first rear limb  34  of FIG. 4A is located behind the position of the first rear limb  34  of FIG. 2A by a distance that equals twice the eccentricity  38  of the attachment of the first bell crank  30  to the first crank shaft  28 . Since the first and second sides of the apparatus are symmetrical and have a 180 degree phase differential between them, it necessarily follows that when the first rear limb  34  and first front limb  36  are positioned as shown in FIG. 2A, then the second rear limb  56  and second front limb  58  are positioned as shown in FIG.  4 A. This can be seen more clearly in FIG.  6 B. 
     The last phase of the walking sequence is shown in FIGS. 5A and 5B. Here, the second rear limb  56  begins to rise while the first rear limb  34  is stationed firmly and flatly on the ground. As a result, the second rear limb  56  makes a step with a height  40  that is equal to the eccentricity  38  of the attachment of the second crank shaft  50  to the second bell crank  52 . At the same time, the first front limb  36  is almost completely flat on the ground with just a slight tilt toward the rear of the apparatus. It also follows that as the first side of the apparatus is positioned as shown in FIG. 5A that the second side of the apparatus is positioned as shown in FIG. 3A because of the symmetry of the apparatus and the maintenance of the 180 degree phase differential between the two sides of the apparatus. 
     FIG. 6A shows the order and placement of the different limbs as the apparatus walks in a radius turn. It should be noted that at certain times of the walking sequence that only three legs are in contact with the ground. This can cause the center of gravity of the apparatus to come dangerously close to the edge of the stability envelope of the apparatus and may cause the apparatus to topple. Consequently, it is preferable that sixty percent of the weight of the apparatus be located forward of the front legs of the apparatus. The batteries  80  used to power the motors of the apparatus should be located near the front of the apparatus in order to achieve this objective (see FIG.  7 B). This can be facilitated by placing a battery compartment door  82  near the front of the apparatus for placing the batteries  80  in the front of the apparatus (see FIG.  1 A). The additional weight of the batteries  80  near the front of the apparatus helps moves the center of gravity of the apparatus toward the front of the apparatus and further within the stability envelope of the apparatus when it is only supported by three limbs (see FIG.  1 B). This, in turn, provides for a more stable apparatus while it is walking. 
     In addition, FIGS. 6B,  6 C, and  6 D show how this apparatus, using the walking sequence depicted by FIGS. 2A,  2 B,  3 A,  3 B,  4 A,  4 B,  5 A, and  5 B, can walk forward, reverse, and turn left or right conventionally. When the first crank shaft  28  rotates in a counter clockwise direction and the second crank shaft  50  rotates in a clockwise direction, the apparatus walks in a forward direction. When these crankshafts are reversed, then the apparatus walks in a reverse direction. Finally, when either the first side or second side of the apparatus are sped up, the lateral phase differential of 180 degrees is disturbed and the sequences of the first side of the apparatus as shown in FIG. 6B are shifted with respect to the second side. Hence, the apparatus turns toward the direction of the slower moving side of the apparatus giving it the ability to turn in a prescribed radius. 
     FIGS. 6E,  6 F,  6 G, and  6 H show how this embodiment of the present invention can execute a turn on its axis. First, the direction of one set of limbs is reversed with respect to the other set of limbs, thereby overcoming the force exerted by the first  70  and second  74  compression springs by forcibly reversing the direction of one of the motors. This is done until a counter phase of 90 degrees is achieved. At this point, the first front limb  36  and second front limb  58  should be in phase with each other while the first rear limb  34  and second rear limb  56  are 90 degrees out of phase. The motion of the legs will then cause the apparatus to turn on axis. Once the turning is complete, the force exerted by the reversed motor is removed until the force of the first  70  and second  74  compression springs causes the phase differential of the first bell crank  30  and second bell crank  52  to return to 180 degrees with both sets of limbs running in the same direction. After the original phase differential has been restored, the apparatus will walk again in a straight line. With all the aforementioned features, this apparatus can walk in a forward fashion, in a reverse fashion, turn left or right in a conventional manner, or turn on its axis. Changing walking patterns by phase shifting is usually accomplished in 1 rotation of the bell crank and takes under 0.5 seconds. Furthermore, phase restoration necessitated by friction, binding or obstruction of the apparatus also occurs within 1 revolution of the bell crank. 
     Another feature of this embodiment is that there is a third motor attached to the apparatus that is capable of providing power to the apparatus for non-ambulatory movement. Examples of such movement include wagging its tail  90 , moving its head  92 , sitting down, lying down, standing, and moving its mouth  94  (see FIGS.  8 A- 8 H). Referring to FIG. 7A, an animation motor  84  and animation gears  86  are shown to give an example of how such movement can be accomplished. These components are connected by linkages  88  to the tail pivot point  96  which is connected to the tail  90 . As the motor  84  drives the linkages  88 , the tail will make a wagging motion. Similar setups can be provided for other types of movement so that this embodiment of the invention can more closely mimic canine attributes than prior art devices. 
     A possible variation of this invention is one in which the apparatus is controlled by a main board processor  98  that can process signals that communicate to the apparatus any stimuli found in its environment (see FIG.  7 C). This may be accomplished by way of LED eyes  100 , wall LEDS  102 , an object LED  104 , and a floor LED  106  that send out infrared transmissions which will bounce off objects, e.g., a moving ball, or detect chasms, e.g., a set of stairs, in its environment. The reflected signals are then picked up by a sensor  108  which transmits a corresponding signal to the main board processor  98 . The main board processor  98  then decides whether there is a moving object present, such as a ball, that should be pursued or an obstruction that should be avoided. Next, the appropriate response is sent which will cause either the first  76  or second regulator  78 , in the form of standard H bridge circuits (see FIG.  12 ), to speed up their respective motors, causing the apparatus to turn, conventionally or on axis, in the proper direction. 
     Another possible variation of this invention is one in which the apparatus is remotely controlled using a radio frequency transmission. The user could then simply use a remote controller, similar to those used for remote controlled model cars, to send a signal to the remote receiver telling it in which direction the user wishes the apparatus to turn. Then the remote receiver would cause either the first  76  or second regulator  78  to speed up the corresponding motor causing the apparatus to turn, conventionally or on axis, in the desired direction. 
     Yet another embodiment includes two microphones  112  that are placed on the head  92  of the apparatus where the ears of a dog would usually be. These microphones  112  can pick up noise in the apparatus&#39; environment, such as the user&#39;s voice, to determine how the apparatus should move. This can be achieved when the signals from the microphones  112  reach the main board processor  98  which then decides whether the apparatus should pursue the sound or whether the sound itself is telling the apparatus in which manner or direction to move. Next, the main board processor  98  transmits the correct message which then tells one of the regulators to speed up or slow down to produce the desired movement. Often this version will also include a speaker  114  so that the apparatus can bark as it opens its mouth  94  in response to the user&#39;s voice or other sounds in its environment. In the case where the user&#39;s voice is used as a remote control, the user can tell the apparatus to walk, turn, stop, and bark. 
     Referring to FIG. 9, the embodiment shown is capable of simulating different canine behaviors depending upon the stimuli found in its environment by implementing a high level flow chart. The first step in the flow chart is the power on step  122  that is initiated either by the user or by some type of timer. It is at this time that the apparatus resets all settings to their proper original values. The next step is the self-test  124  portion of the high level flow chart. During this step, the main board processor  98  checks all input devices to make sure that all systems are functioning properly. If not, the apparatus indicates a soft fail until the problem is rectified. 
     Then, the main board processor  98  scans for the inputs mentioned above including the owner&#39;s voice, other sound sources, light, overload, tilt, and reflections of infrared rays that have been bounced off objects in its environment. This is called the scanned inputs  126  phase. Other types of input include signals generated by the nose switch  116 , pat switch  118  located on the top of the apparatus&#39; head, and pet switches  120   a ,  120   b , and  120   c  located along the back of the apparatus (see FIGS. 1A,  7 C, and  13 ). The main board processor  98  prioritizes the data to determine what level of behavior is appropriate. 
     In determining the appropriate behavior to exhibit, the preferred embodiment of the present invention uses a stimuli accumulator that works as follows in the prioritize input data  128  step. Stimuli inputs such as voice, pet, touch, and motion input are quantified by accumulating the number of occurrences of these inputs over a five minute period during which they occur. These inputs are termed interaction parameters and are assigned “A” as a variable, the value of which is the number as determined above. Similarly, the environment parameters include sound inputs and light inputs and are assigned a variable “B”,the value of which is calculated in a similar way as done for the interaction variables. Finally, the terrain parameters include floor, wall, tilt, and limb inputs and are assigned a variable “C”,the value of which is calculated in the same way as mentioned for both the environment and interaction parameters. Once the main board processor  98  has determined these variables, it compares their values once a minute as shown in Table 1 to decode what state the apparatus should exhibit whether it be sad, happy, sick, sleepy, etc. It should be noted that since there are more inputs being measured for variables “A” and “C” that this comparison is weighted, thus the apparatus is more likely to exhibit states such as happy and hyper than sleepy or sick just like a real canine. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 MOOD DECODER TABLE 
               
            
           
           
               
               
            
               
                 STATES 
                 DECODE 
               
               
                   
               
               
                 A = B + A = C 
                 SAD 
               
               
                 A = B + A &gt; C 
                 HAPPY 
               
               
                 A = B + A &lt; C 
                 HYPER 
               
               
                 A &gt; B + A = C 
                 HAPPY 
               
               
                 A &gt; B + A &gt; C 
                 HAPPY 
               
               
                 A &gt; B + A = C 
                 HYPER 
               
               
                 A &lt; B + A = C 
                 SAD 
               
               
                 A &lt; B + A &gt; C 
                 SLEEPY 
               
               
                 A &lt; B + A &lt; C 
                 SICK 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 TYPES OF ACTIVITIES 
               
            
           
           
               
               
               
               
            
               
                 OBEY 
                 WAIT 
                   
                   
               
               
                 Response to 
                 Lower Power 
                 EXPLORE 
                 TALK 
               
               
                 User Input 
                 Activities 
                 Walk/Turn 
                 Make Noise 
               
               
                   
               
               
                 Tricks 
                 Static Pose 
                 Locomotion 
                 Moods Status 
               
               
                 Interaction 
               
               
                 Some Moods 
                 Dynamic Pose 
                 Some Moods 
                 Annunciation 
               
               
                   
                   
                   
                 of Moods 
               
               
                 Annunciation 
                 (Display Mood) 
                 Seeking/Searching 
               
               
                 (Yes/No) 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 PASSIVE STATE (NO USER INTERACTION) 
               
               
                 ACTIVITIES PERCENTAGE 
               
               
                 (user interaction by pressing the head switches for 5 sec forces obey mode 
               
               
                 for any mood, listening for obey will occur after the completion of the 
               
               
                 current activity) 
               
               
                 IF THE USER SAYS “STAY” EXPLORE AND WALKING MODES 
               
               
                 ARE CANCELLED 
               
               
                 “COME” RESTORES EXPLORE 
               
            
           
           
               
               
               
               
               
            
               
                   
                 OBEY 
                 WAIT 
                 EXPLORE 
                 TALK 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
               
            
               
                   
                 HYPER 
                 10% 
                 50% 
                 30%  
                 10% 
               
               
                   
                 HAPPY 
                 50% 
                 30% 
                 10%  
                 10% 
               
               
                   
                 SAD 
                 10% 
                 70% 
                 5% 
                 15% 
               
               
                   
                 SLEEPY 
                 10% 
                 70% 
                 5% 
                 15% 
               
               
                   
                 SICK 
                  5% 
                 80% 
                 1% 
                 14% 
               
               
                   
                   
               
            
           
         
       
     
     Table 2 shows how these states of the apparatus correspond to the output behavior of the apparatus whether it be to obey, wait, explore, or talk. The apparatus executes a program depending on what state it is in. For example, the apparatus will wag its tail whenever it is hyper or happy. All non-ambulatory movements of the apparatus are controlled in this way. Table 3 shows how the apparatus apportions its behavior depending on the state of the apparatus when there is no user interaction. This is done based on a percentage of time displaying that type of behavior. For instance, if the apparatus is determined to be sick under Table 1 and there is no user interaction, the apparatus will display a waiting type of behavior eighty percent of the time. Through this type of programming, the apparatus can effectively implement the high level flow chart as shown in FIG.  9 . 
     If there is no input, then the apparatus will simulate a sleep mode  130  where there is no output. If the input level is low, then the apparatus exhibits a normal mode  132  of behavior where it will seek, sit, wag its tail, speak and look around like a dog normally does. It will also seek communication from the user or the environment using its input devices. If the input level is medium, then the apparatus will imitate a slow activity  134  level of behavior where it is more active in the level of output it generates. For instance, it may seek out an object in its environment. However, if the input is high then the apparatus begins to behave in a manner that is consistent with the way a dog does when it is threatened. The apparatus then stops its normal activity  136  and applies an iterative process where it tries to apply some corrective action  138  to remedy the problem. The problem could take the form of being confined in a tight area or being pinned down and unable to move. In such situations, the dog may even cry  140  if it is unable to solve the problem. As a result of this interaction between inputs, software, and outputs of the apparatus, it can behave more like a canine than prior art devices. See FIGS. 10 and 11 for more information about this interaction and FIGS. 12 and 13 for the wiring schematics of the entire apparatus. 
     As can be seen, the described embodiments fulfill the need for a self-phase synchronized walking and turning quadruped apparatus that can respond to stimuli in its environment in a canine way. It is also readily apparent to those skilled in the art that the features of the present invention are capable of being applied to apparati with less and more than four legs as well. While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.