Abstract:
A torso part ( 2 ) and a backpack part ( 6 ) of a humanoid robot are commonly formed by a shell that defines an inner space that accommodates a heat generating component such as a control computer ( 31 ) and a power module ( 32, 33 ). The shell comprises an air vent hole ( 45, 46 ) provided on one lateral side of the shell, an air inlet hole ( 47, 48 ) provided on the other lateral side of the shell and a powered fan ( 49 ) provided immediately inside the air vent hole. Because the cooling air can flow laterally across the inner space, the entire part of the heat generating component can contact the air flow, and a uniform cooling effect can be achieved with a minimum power consumption and a minimum noise generation.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to a cooling arrangement for a humanoid robot having heat generating components such as a control computer and a power module inside a shell that forms at least a torso part of the robot, and in particular to a cooling arrangement for a humanoid robot that can improve the cooling efficiency.  
       BACKGROUND OF THE INVENTION  
       [0002]     Various forms of humanoid robots have been developed. Unlike stationary industrial robots that are employed in painting, welding, assembling and other manufacturing work, a humanoid robot is required to be more compact because of the need to move about in a limited space with a limited power resource. A typical humanoid robot includes a battery, a control computer and a power module for the purpose actuating various drive motors for moving the arms and legs thereof in a highly coordinated fashion, and such components are typically accommodated in the torso part of the robot as there is no other available space. When the torso part does not provide an adequate space, a backpack portion may be added to the back part of the torso part so as to jointly define a larger space.  
         [0003]     Such electric and electronic components generate a significant amount of heat during the operation of the robot, but the internal temperature of the robot must be kept below a certain temperature for the electric and electronic components to be able to operate properly. The inner space accommodating such components are typically so packed and enclosed that natural ventilation would not be adequate to control the inner temperature of the robot.  
         [0004]     According to the previous proposal disclosed in Japanese patent laid open publication No. 2002-154083, downwardly directed air inlet slots are formed in a lower part (of the two lateral sides and rear side) of a backpack portion of the robot, and a horizontally directed air vent hole is formed in an upper part of the rear side of the backpack. A vent fan is provided inside the air vent hole to lower the internal pressure by expelling warm air from the air vent hole and admit fresh air from the air inlet hole. This provides an adequate air flow to cool the interior of the backpack part of the robot.  
         [0005]     However, there is some room for improvement in this previous proposal. The air drawn from the lower part of the backpack portion tends to flow along the lateral sides of the inner components than along the back side thereof, and the central back part of the inner components is less effectively cooled. Also, the air flows along a somewhat tortuous path, and a pressure drop of the air flow is significant. For these reasons, a relatively large power is required for the fan to effectively cool the entire inner components. This is not desirable because of a large power consumption and a high noise level. A humanoid robot is often required to carry the power source such as a battery, and it is highly desirable to minimize the power consumption of such a fan.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     In view of such problems of the prior art, a primary object of the present invention is to provide a cooling arrangement for a humanoid robot that can improve the cooling efficiency.  
         [0007]     A second object of the present invention is to provide a cooling arrangement for a humanoid robot that can save power consumption and reduce noises.  
         [0008]     These and other objects of the present invention can be accomplished by providing a cooling arrangement for a humanoid robot including a shell having a pair of lateral sides, a front side and a rear side so as to form at least a torso part of the robot, the shell defining an inner space that accommodates a heat generating component, wherein: the shell comprises an air vent hole provided on one of the lateral sides of the shell, an air inlet hole provided on the other lateral side of the shell and a powered fan provided immediately inside of at least one of the air vent hole and the air inlet hole.  
         [0009]     Because the cooling air can flow laterally across the inner space, the entire part of the heat generating component, such as a control computer, a power module and a gyro, can contact the air flow, and a uniform cooling effect can be achieved with a minimum power consumption and a minimum noise generation.  
         [0010]     The shell may further comprise a backpack portion that defines the inner space jointly with the torso portion so that the volume of the inner space may be maximized. In such case, the air inlet hole and air vent hole may be formed on the lateral sides of the backpack portion. Because the robot is often required to face a human being, it is desirable to prevent any warm or hot air from being blown toward the human being. For this purpose, the air vent hole may be provided with a member for directing the air flow in a direction more rearward than a lateral direction.  
         [0011]     For an improved cooling effect, the shell may further comprise a torso air outlet provided on at least one of the lateral sides of the torso part of the shell, a torso air inlet hole provided in a downward facing part of the shell and a powered fan provided immediately inside of at least one of the torso air vent hole and the torso air inlet hole. Because the cooling air is allowed to flow upward centrally from a lower part of the torso part, the entire torso part can be effectively and uniformly cooled. Also, because the air inlet hole faces downward, it is possible to prevent any foreign matter from dropping or otherwise being introduced into the air inlet hole.  
         [0012]     If the robot further comprises a temperature sensor for detecting a temperature of the inner space and controlling the fan according to the detected temperature, the consumption of power and emission of noises can be minimized because the fan may be activated only when needed.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Now the present invention is described in the following with reference to the appended drawings, in which:  
         [0014]      FIG. 1  is a front view of a humanoid robot embodying the present invention;  
         [0015]      FIG. 2  is a left side view of the humanoid robot;  
         [0016]      FIG. 3  is a simplified side view of the shell that includes the torso part and the backpack part;  
         [0017]      FIG. 4  is a sectional view taken along line IV-IV of  FIG. 3 ;  
         [0018]      FIG. 5  is a sectional view taken along line V-V of  FIG. 3 ; and  
         [0019]      FIG. 6  is a sectional view taken along line VI-VI of  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     Referring to  FIGS. 1 and 2 ;, the humanoid robot  1  (which is referred to simply as a robot hereinafter) embodying the present invention comprises a torso  2 , a head  3 , a pair of arms  4 L and  4 R, a pair of legs  5 L and  5 R and a backpack box  6 . Each arm  4 L ( 4 R) includes an upper arm  7 L ( 7 R), a lower arm  8 L ( 8 R) and a hand  9 L ( 9 R). Likewise, each leg includes an upper leg  10 L ( 10 R), a lower leg  11 L ( 11 R) and a foot  12 L ( 12 R).  
         [0021]     The head  3  is connected to the torso  2  via a neck joint  21 . Each upper arm  7 L ( 7 R) is connected to the torso  2  via a shoulder joint  22  at an upper end thereof and connected to the corresponding lower arm  8 L ( 8 R) via an elbow joint  23  at a lower end thereof. The lower arm  8 L ( 8 R) is in turn connected to the corresponding hand  9 L ( 9 R) via a wrist joint  24 . A middle part of each upper arm  7 L ( 7 R) is provided with an upper arm joint  25  so that the upper and lower parts of the upper arm can be rotated relative to each other around an axial line extending centrally of the upper arm in an axial direction. Similarly, each upper leg  10 L ( 10 R) is connected to the torso  2  via a hip joint  26  at an upper end thereof and connected to the lower leg  11 L ( 11 R) via a knee joint  27  at a lower end thereof. The lower leg  11 L ( 11 R) is in turn connected to the foot  12 L ( 12 R) via an ankle joint  28 . In  FIGS. 1 and 2 , these joints  22  to  28  are indicated by dotted line circles.  
         [0022]     Referring to FIGS.  3  to  6 , the torso  2  and backpack box  6  consist of an integral shell defining a common interior. A lower part of the torso  2  accommodates a control computer  31  for controlling the action of the robot  1 , and an upper front part of the backpack box  6  accommodates a DC-DC converter  32 . The backpack box  6  further accommodates therein a battery  33  in an upper rear part thereof and a gyro  34  in a lower part thereof. The control computer  31  is illustrated as a rectangular box in  FIGS. 4 and 6 , but in fact includes a plurality of circuit boards that are stacked one over the other in a spaced relationship. The major plane of each circuit board may extend either in a vertical direction, horizontal or oblique direction.  
         [0023]     The torso  2  is provided with a pair of vent holes  41  and  42  on either side thereof and an air inlet hole  43  in a lower front part thereof. As best shown in  FIG. 4 , each side vent hole  41  ( 42 ) consists of five vertical slots that are adapted to direct air flow obliquely rearward by louver vanes, and a vent fan  44  is provided immediately inside each vent hole  41  ( 42 ). The louver blades are used in the illustrated embodiment to direct the air flow in an obliquely rearward direction, but other members such properly directed ducts, pipes and other members can be used for a similar effect. The air inlet hole  43  consists of five slots extending laterally and facing downward in a lower central part of the torso  2 . As shown in  FIGS. 4 and 6 , the torso  2  is also provided with a first temperature sensor SI for detecting the temperature of the area around the control computer  31 .  
         [0024]     The backpack box  6  is provided with a first side air inlet  45  and a second side air inlet  46  on the left side thereof one behind the other and a first side air inlet  47  and a second side air inlet  48  on the right side thereof similarly one behind the other. The right and left first vent holes  45  and  47  in the front are located in that parts that correspond to the DC-DC converter  32  and the gyro  34 . The right and left second vent holes  46  and  48  in the rear are located in the parts that correspond to the battery  33 .  
         [0025]     The right and left first vent holes  45  and  47  in the front each consist of five vertical slots which are adapted to direct air flow obliquely rearward by louver blades. Three vent fans  49  are provided immediately inside the first left vent hole  45  and are arranged along the length of the slots. The lowermost fan opposes the gyro  34 , and the other two fans oppose the DC-DC converter  32 . The right and left second vent holes  46  and  48  in the rear each consist of five vertical slots which are adapted to direct air flow obliquely rearward by louver blades. A pair of vent fans  49  are provided immediately inside the second left vent hole  46  and are arranged along the length of the slots, and both oppose the battery  33 . As illustrated in FIGS.  4  to  6 , the backpack box  6  is provided with a second temperature sensor S 2  for detecting the temperature of the area surrounding the DC-DC converter  32  and battery  33 , and a third temperature sensor S 3  for detecting the temperature of the area surrounding the gyro  34 .  
         [0026]     The mode of operation of this system is described in the following. When the robot  1  walks or otherwise exerts efforts, the battery  33  and DC-DC converter  34  that supply electric power to the drive motors for the arms  4 L and  4 R and legs  5 L and  5 R generate heat. The gyro  34  that enables the robot  1  to maintain balance and the control computer  31  that carries out various arithmetic operations also generate heat. During the operation of the robot  1 , the vent fans  44  in the torso  2  and the vent fans  49  in the backpack box  6  turn and remove the heat to the outside. The fans may keep turning at all times, but it is more preferable to operate the fans only when needed as will be described hereinafter.  
         [0027]     The air heated by the control computer  31  is drawn by the vent fans  44  in the torso  2  as illustrated in  FIG. 4 , and is expelled in an obliquely rearward direction from the right and left vent holes  41  and  42  of the torso  2 . This causes a drop in the pressure inside the torso  2 , and external air is drawn from the inlet hole  43  as a result. The drawn air flows through the gaps between the circuit boards of the control computer  31  before it is drawn out of the torso  2  by the vent fans  44 . As a result, the control computer  31  is evenly cooled by the air flow, and is allowed to operate in a stable manner. Because the air inlet hole  43  is provided in the lower side of the front part of the torso  2 , foreign matters falling from above are effectively kept off from the interior of the torso  2 . Because the air is expelled from the interior of the torso  2  in an obliquely rearward direction from either side thereof, hot air from the vent holes would not be blown onto persons who may be located in front of or near either side of the robot.  
         [0028]     As shown in  FIGS. 4 and 5 , the air warmed by the battery  33 , DC-DC converter  32  and gyro  34  is drawn by the vent fans  49  in the backpack box  6  and is expelled obliquely rearward from the first and second vent holes  45  and  46  formed on the left side of the backpack box  6 . As a result, the battery  33 , DC-DC converter  32  and gyro  34  can be cooled evenly by the air flow, and the interior of the backpack box  6  is prevented from becoming excessively hot. The air expelled from the first and second vent holes  45  and  46  on the left side of the backpack box  6  is directed obliquely rearward so that the hot vent air would not be blown onto the persons who may be located in front of or on one side of the robot  1 .  
         [0029]     The first and second vent holes  47  and  48  on the right side draw air from outside to make up for the air removed from the first and second vent holes  45  and  46  on the left side. Thereby, cooling air flows across the battery  33 , DC-DC converter  32  and gyro  34 , and effectively cools them.  
         [0030]     In the illustrated embodiment, the vent fans  44  in the torso  2  operate in dependence on the surrounding temperature of the control computer  31  detected by the first temperature sensor S 1 , and are made to rotate at a low speed or to stop when the surrounding temperature is low. The fans  49  in the backpack box also operate in dependence on the surrounding temperature of the battery  33  and DC-DC converter  32  detected by the second temperature sensor S 2  and/or the surrounding temperature of the gyro  34  detected by the third temperature sensor S 3 , and are made to rotate at a low speed or to stop when the surrounding temperatures are low. Thereby, the power of the battery  33  would not be wasted, and the noises of the fans can be reduced.  
         [0031]     In the illustrated embodiment, the fans  44  and  49  were provided immediately inside the corresponding air vent holes to draw air out of the inner space, but it is also possible to provide similar fans immediately or otherwise inside the corresponding air inlet holes as indicated by numerals  44 ′ and  49 ′ to draw air into the inner space. In the latter case, the fans raises the pressure of the inner space and push the warm air out of the inner space from the air vent holes.  
         [0032]     Although the present invention has been described in terms of preferred embodiments thereof, it is obvious to a person skilled in the art that various alterations and modifications are possible without departing from the scope of the present invention which is set forth in the appended claims. For instance, although the air inlet hole was provided in the downwardly facing part of the torso, but may also be formed in a side part of the torso in a similar fashion as the air inlet holes formed in the backpack box. The control computer and DC-DC converter may be accommodated either in the torso or the backpack box. The structures and configurations of the torso and backpack box and the layout of the vent holes and air inlet holes can be freely modified without departing from the spirit of the present invention. The vent fans may consist of not only axial fans but also other forms of fans such as sirocco fans and radial fans.  
         [0033]     The contents of the original Japanese patent application on which the Paris Convention priority claim is made for the present application are incorporated in this application by reference.