Abstract:
A robotic hand assembly comprising: a hand section comprising: at least one digit provided with at least one actuatable joint; and a control section comprising: at least one actuation device, the at least one actuation device comprising: a sensing module configured to sense a force applied to a tendon coupled at a first end to the at least one actuatable joint; and an actuation module configured to actuate the at least one actuatable joint.

Description:
This application claims the benefit of U.S. Provisional Application No. 61/227,738, filed on Jul. 22, 2009, which is hereby incorporated by reference herein. 
    
    
     TECHNICAL FIELD 
     The invention relates to a robotic hand. In particular, the invention relates to a motorised robotic hand. In one embodiment, the robotic hand has improved force sensing. In another embodiment, the robotic hand has improved control of digit movement. 
     BACKGROUND 
     It is desirable to use robotic devices in many industries. U.S. Pat. No. 7,168,748 B2 entitled “Intelligent, Self-Contained Robotic Hand” discloses a known robotic hand comprising three fingers. However, it is desirable for a robotic hand to imitate a human hands gripping functionality and range of movement. 
     The human hand is capable of numerous, and a wide range of, movements. In addition, the human hand is capable of gripping objects of numerous different sizes using a wide range of forces from very delicate to very strong. The vast range of movements and functionality are difficult to mimic, since each additional range of movement requires the use of a further joint in the robotic hand. Each joint of a robotic hand requires a power supply and control means, both of which require connection to the joint. This results in a highly complex arrangements of wires, which multiplies for every additional joint. The large numbers of wires results in robotic hands being complex to produce and bulky, which in turn reduces the dexterity of the robotic hand. 
     The present invention aims to provide a robotic hand which more closely mimics a human hand. In addition, the present invention aims to provide a robotic hand which has more accurate control and which is less bulky than known robotic hands. 
     SUMMARY 
     According to one embodiment of the invention a robotic hand assembly is provided. The robotic hand assembly comprising: a hand section comprising: at least one digit provided with at least one actuatable joint; and a control section comprising: at least one actuation device, the at least one actuation device comprising: a sensing module configured to sense a force applied to a tendon coupled at a first end to the at least one actuatable joint; and an actuation module configured to actuate the at least one actuatable joint. 
     According to another embodiment of the invention the tendon comprise a first tendon and a second tendon. 
     According to another embodiment of the invention the sensing module comprises: a first force sensor; a second force sensor; and a connection bar coupled between the first and second force sensors. 
     According to another embodiment of the invention the first force sensor is configured to sense a force applied to the first tendon and the second force sensor is configured to sense a force applied to the second tendon. 
     According to another embodiment of the invention the first tendon is routed over the connection bar adjacent to the first force sensor, and the second tendon is routed over the connection bar adjacent to the second force sensor. 
     According to another embodiment of the invention the sensing module further comprises: a spool, wherein a second end of the tendon is coupled to the spool. 
     According to another embodiment of the invention the spool comprises a first spool and a second spool, and wherein the second end of the first tendon is coupled to the first spool and the second end of the second tendon is coupled to the second spool. 
     According to another embodiment of the invention the first spool and the second spool are configured to be moveable relative to one another, in order to adjust a tension in the first and second tendons. 
     According to another embodiment of the invention the sensing module further comprises: a securing device configured to secure the first and second spools relative to one another. 
     According to another embodiment of the invention the at least one actuation device further comprises: a tensioner module configured to apply tension the tendon. 
     According to another embodiment of the invention the tensioner module comprises: biasing means configured to bias the tendon in a first direction to apply tension to the tendon. 
     According to another embodiment of the invention the biasing means comprises: a pulley provided in a recess, wherein the tendon is routed around the pulley; and a biasing device coupled to the pulley biasing the pulley towards a first end of the recess to apply tension the tendon. 
     According to another embodiment of the invention the biasing device comprises a spring. 
     According to another embodiment of the invention the actuation module comprises a motor and gears. 
     According to another embodiment of the invention the actuation module further comprises control means for controlling the motor and gears. 
     According to another embodiment of the invention the control means comprises a printed circuit board. 
     According to another embodiment of the invention the control section comprises: a cooling device configured to cool the at least one actuation module. 
     According to another embodiment of the invention the robotic hand assembly further comprises: a routing plate configured to enable routing of the tendons to the associated actuation device. 
     According to another embodiment of the invention the routing plate comprises: a square routing plate; or a rectangular routing plate; or a hexagonal routing plate, or a circular routing plate. 
     According to another embodiment of the invention the routing plate comprises a plurality of grooves, each groove for routing a tendon. 
     According to one embodiment of the invention a sensing module for sensing a force applied to a tendon coupled at a first end to an actuatable joint is provided. The sensing module comprising: a first force sensor; a second force sensor; and a connection bar coupled between the first and second force sensors. 
     According to another embodiment of the invention the tendon comprise a first and second tendon, and wherein the first force sensor is configured to sense a force applied to the first tendon and the second force sensor is configured to sense a force applied to the second tendon. 
     According to another embodiment of the invention the first tendon is routed over the connection bar adjacent to the first force sensor, and the second tendon is routed over the connection bar adjacent to the second force sensor. 
     According to another embodiment of the invention the sensing module further comprises: a spool, wherein a second end of the tendon is coupled to the spool. 
     According to another embodiment of the invention the tendon comprise a first and second tendon, wherein the spool comprises a first spool and a second spool, and wherein the second end of the first tendon is coupled to the first spool and the second end of the second tendon is coupled to the second spool. 
     According to another embodiment of the invention the first spool and the second spool are configured to be moveable relative to one another, in order to adjust a tension in the first and second tendons. 
     According to another embodiment of the invention the sensing module further comprises: a securing device configured to secure the first and second spools relative to one another. 
     According to one embodiment of the invention a tensioner module for applying tension to a tendon coupled at a first end to an actuatable joint is provided. The tensioner module comprising: a pulley provided in a recess, wherein the tendon is routed around the pulley; and a biasing device coupled to the pulley biasing the pulley towards a first end of the recess to apply tension the tendon. 
     According to another embodiment of the invention the biasing device comprises a spring. 
     According to one embodiment of the invention an actuation device for actuating a joint is provided. The actuation device comprising: a sensing module configured to sense a force applied to a tendon coupled at a first end to the joint; and an actuation module configured to actuate the at least one joint. 
     According to another embodiment of the invention the actuation device further comprises: a tensioner module configured to apply tension the tendon. 
     According to another embodiment of the invention the actuation module comprises a motor and gears. 
     According to another embodiment of the invention the actuation module further comprises control means for controlling the motor and gears. 
     According to another embodiment of the invention the control means comprises a printed circuit board. 
     According to another embodiment of the invention the control section comprises: a cooling device configured to cool the at least one actuation module. 
     According to one embodiment of the invention a robotic finger digit is provided. The robotic finger digit comprising: a distal finger joint coupled between a distal finger part and a middle finger part; a middle finger joint coupled between the middle finger part and a proximal finger part; an extend tendon coupled at a first end to the distal finger joint, and coupled at a second end to an actuation device; and a flex tendon coupled at a first end to the distal finger joint, and coupled at a second end to the actuation device, wherein the actuation device is configured to move the extend tendon and the flex tendon substantially the same distance in order to flex and/or extend the robotic finger digit. 
     According to another embodiment of the invention the distal finger joint is configured to enable the distal finger part to move about a first axis. 
     According to another embodiment of the invention the middle finger joint is configured to enable the middle finger part to move about a second axis, parallel to the first axis. 
     According to another embodiment of the invention the actuation device comprises a motor, or an air muscle device. 
     According to another embodiment of the invention the robotic finger digit further comprises: a loopback tendon coupled at a first end to the distal finger joint, and configured to bias the robotic finger digit in a extend position. 
     According to another embodiment of the invention the robotic finger digit further comprises: a biasing device provided at a second end of the loopback tendon. 
     According to another embodiment of the invention in use, activation of the extend tendon and the flex tendon results in actuation of the distal finger joint and the middle finger joint. 
     According to one embodiment of the invention a wrist joint assembly for a robotic hand is provided. The wrist joint assembly comprising: a first wrist joint configured to enable the robotic hand to move about a first axis, and coupled to a first wrist joint tendon; a second wrist joint configured to enable the robotic hand to move about a second axis orthogonal to the first axis, and coupled to a second wrist joint tendon, the second wrist joint comprising a substantially circular guide surface for the second wrist joint tendon; and an actuation device configured to actuate the first wrist joint tendon and the second wrist joint tendon substantially the same distance in order to actuate the first and second wrist joints. 
     According to another embodiment of the invention the first wrist joint tendon comprise a first flex wrist joint tendon and a first extend wrist joint tendon, and wherein the second wrist joint tendon comprise a second flex wrist joint tendon and a second extend wrist joint tendon 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       For a better understanding of the invention and as to how the same may be carried into effect reference will now be made, by way of example only, to the accompanying figures, in which: 
         FIG. 1A  illustrates a motorised robotic hand; 
         FIG. 1B  illustrates a motorised robotic hand; 
         FIG. 1C  illustrates schematically a motorised robotic hand; 
         FIG. 2  illustrates schematically components of a robotic hand; 
         FIG. 3A  illustrates schematically components for actuating a digit of a robotic hand; 
         FIG. 3B  illustrates schematically components for actuating a digit of a robotic hand; 
         FIG. 4A  illustrates schematically a digit of a robotic hand; 
         FIG. 4B  illustrates schematically a digit of a robotic hand; 
         FIG. 5  illustrates schematically a perspective view of components for actuating a digit of a robotic hand; 
         FIG. 6  illustrates schematically a side view cut-through of the components of  FIG. 5 ; 
         FIG. 7  illustrates schematically a side view of a tensioner module; 
         FIG. 8  illustrates schematically a perspective view of a tensioner module; 
         FIG. 9  illustrates schematically another side view of a tensioner module; 
         FIG. 10  illustrates schematically a perspective view of a sensing module; 
         FIG. 11  illustrates schematically another perspective view of a sensing module; 
         FIG. 12  illustrates schematically a side view cut-through of a sensing module; 
         FIG. 13  illustrates schematically a perspective view of a spool; 
         FIG. 14  illustrates schematically another perspective view of a spool; 
         FIG. 15  illustrates schematically an arrangement of tendons for controlling movement of a robotic wrist section; 
         FIG. 16A  illustrates a perspective view of an underside of a routing plate; and 
         FIG. 16B  illustrates a perspective view of a routing plate. 
     
    
    
     DETAILED DESCRIPTION 
     Additional advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and accompanying figures or may be learned by practice of the invention. 
       FIGS. 1A ,  1 B and  1 C illustrate a motorised robotic hand. As can be seen from  FIGS. 1A ,  1 B and  1 C, a motorised robotic hand comprises a hand section  10  and a control section  20 . The hand section  10  comprises four finger digits  102 ,  104 ,  106 ,  108  and a thumb digit  110 , which substantially imitate the digits of a human hand, a palm section  150 , which substantially imitates a human palm, and a wrist section  140 ,  142 ,  144 , which substantially imitates a human wrist. The control section  20  comprises a plurality of actuation devices, each actuation device comprising a tensioner module  300 , a sensing module  400  and an actuation module  500 .  FIG. 1A  illustrates four actuation devices, whilst  FIG. 1B  illustrates eight actuation devices. Each actuation device enables movement of one component, such as one joint of a digit, of the robotic hand section  10 . As can be seen from  FIG. 1B , a fan may be provided in order to cool the actuation modules  500 . 
       FIG. 2  illustrates schematically exemplary components of the robotic hand section  10 . Each finger digit  102 ,  104 ,  106 ,  108  includes a distal finger part  112 , a middle finger part  114  and a proximal finger part  116 . Only the distal, middle and proximal finger parts  112 ,  114 ,  116  of finger digit  102  are labelled in  FIG. 2 . However, it is clear from  FIG. 2  that finger digits  104 ,  106  and  108  also include finger parts  112 ,  114 ,  116 . 
     The distal finger part  112  and the middle finger part  114  are connected by a distal finger joint  118 . The distal finger joint  118  enables the distal finger part  112  to move about an X axis X 1 , illustrated in  FIG. 2 , with respect to the middle finger part  114 . The middle finger part  114  and the proximal finger part  116  are connected by a middle finger joint  120 . The middle finger joint  120  enables the middle finger part  114  to move about an X axis X 2 , illustrated in  FIG. 2 , with respect to the proximal finger part  116 . Finally, the proximal finger part  116  is connected to the palm section  150  by a proximal finger joint  122 . The proximal finger joint  122  enables the proximal finger part  116  to move about an X axis X 3  and about a Y axis Y 1 , illustrated in  FIG. 2 , with respect to the palm section  150 . Axes X 1 , X 2  and X 3  are parallel to one another. Axis Y 1  is orthogonal to axes X 1 , X 2  and X 3 . Only the distal, middle and proximal finger joints  118 ,  120 ,  122  of finger digit  102  are labelled in  FIG. 2 . However, it is clear from  FIG. 2  that finger digits  104 ,  106  and  108  also include finger joints  118 ,  120 ,  122 . 
     The thumb digit  110  includes a distal thumb part  128 , a middle thumb part  130  and a proximal thumb part  132 . 
     The distal thumb part  128  and the middle thumb part  130  are connected by a distal thumb joint  134 . The distal thumb joint  134  enables the distal thumb part  128  to move about a Y axis Y 2 , illustrated in  FIG. 2 , with respect to the middle thumb part  130 . The middle thumb part  130  and the proximal thumb part  132  are connected by a middle thumb joint  136 . The middle thumb joint  136  enables the middle thumb part  130  to move about a Y axis Y 3  and an X axis X 4 , illustrated in  FIG. 2 , with respect to the proximal thumb part  132 . Finally, the proximal thumb part  132  is connected to the palm section  150  by a proximal thumb joint  138 . The proximal thumb joint  138  enables the proximal thumb part  132  to move about an X axis X 5 , and about a Z axis Z 1 , illustrated in  FIG. 2 , with respect to the palm section  150 . Axes Y 2  and Y 3  are parallel to one another. Axes X 4  and X 5  are parallel to one another. Axes X 4  and X 5  are orthogonal to axes Y 2  and Y 3 . Finally, axis Z 1  is orthogonal to axes Y 2  and Y 3 , and axes X 4  and X 5 . 
     First palm joint  124  and second palm joint  126  enable movement of the palm section  150  such as the thumb digit  110  can touch the third and fourth finger digits  106  and  108 . However, other palm sections  150  may also be used. For example, the palm sections  150  illustrated in  FIG. 1C  only comprises a second palm joint  126  to enable movement of the palm section  150 . 
     The hand section  10  is connected to the control section  20  via the wrist section  140 ,  142 . First wrist joint  140  enables the hand section  10  to move about an X axis X 6 , illustrated in  FIG. 2 , with respect to the control section  20  (not illustrated in  FIG. 2 ). Second wrist joint  142  enables the hand section  10  to move about a Y axis Y 4 , illustrated in  FIG. 2 , with respect to the control section  20  (not illustrated in  FIG. 2 ). Axes X 6  and Y 4  are orthogonal to one another. 
     The hand section  10  illustrated schematically in  FIG. 2  is provided for illustrative purposes only and other hand sections  10  comprising different finger and thumb digit arrangements, and different palm and wrist section arrangements may be used in combination with the control section  20  of the invention. 
     Each joint enables movement in a first direction about an axis, and in a second direction, opposite to the first direction, about the axis. For example, in  FIG. 3A , joint  560  enables movement of part  570  in a first direction  580 A about an axis (through the page of  FIG. 3A ), and in a second direction  580 B, opposite to the first direction  580 A, about the axis. In  FIG. 3B , joint  650  enables movement of part  660  in a first direction  670 A about an axis (through the page of  FIG. 3B ), and in a second direction  670 B, opposite to the first direction  670 A, about the axis. 
     Joints  122 ,  136  and  138 , illustrated in  FIG. 2 , can be thought of as essentially two separate joints. Proximal finger joint  122  comprises a first proximal finger joint enabling movement in a first direction about axis X 3 , and in a second direction, opposite to the first direction, about axis X 3 , and a second proximal finger joint enabling movement in a first direction about axis Y 1 , and in a second direction, opposite to the first direction, about axis Y 1 . Middle thumb joint  132  comprises a first middle thumb joint enabling movement in a first direction about axis Y 3 , and in a second direction, opposite to the first direction, about axis Y 3  and a second middle thumb joint enabling movement in a first direction about axis X 4 , and in a second direction, opposite to the first direction, about axis X 4 . Proximal thumb joint  138  comprises a first proximal thumb joint enabling movement in a first direction about axis X 5 , and in a second direction, opposite to the first direction, about axis X 5  and a second proximal thumb joint enabling movement in a first direction about axis Z 1 , and in a second direction, opposite to the first direction, about axis Z 1 . 
     Two tendons are attached, at a first end, to each joint. The two tendons are also connected, at a second end, to an actuation device (such as control section  20  of  FIGS. 1A to 1C ) in order to actuate each joint in the first direction, and in the second direction, opposite to the first direction. An actuation device is required for each joint. 
     In one embodiment, one tendon could be used, looped around and connected to the joint at a mid section. The first and second ends of the tendon being connected to an actuation device in order to actuate the joint in the first direction and in the second direction, opposite to the first direction. 
       FIGS. 3A and 3B  illustrates schematically components for actuating a joint.  FIG. 3A  illustrates schematically a motor driven actuation device (such as control section  20  of  FIGS. 1A to 1C ) and  FIG. 3B  illustrates an air muscle driven actuation device. 
     The motor driven actuation device of  FIG. 3A  comprises a motor  505 ; gears  510 ; a first spool  520 ; a first force sensor  530 A; a second force sensor  530 B; a first tensioner  540 A; a second tensioner  540 B; a first tendon  550 A; a second tendon  550 B; a second spool  560 ; and a part  570 . The motor  505  is connected to the gears  510 , which in turn are connected to the first spool  520 . The first spool  520  is connected to a first end of the first and second tendons  550 A,  550 B, via the first and second force sensors  530 A,  530 B and the first and second tensioners  540 A,  540 B respectively. The first and second tendons  550 A,  550 B are also connected at a second end to the part  570  via the second spool  560 . 
     Activation of the first tendon  550 A in direction +A, by means of the motor  505  and gears  510 , results in rotation of the spool in a first direction about an axis running through the page of  FIG. 3A , and thus movement of the part  570  in a direction  580 A. Activation of the second tendon  550 B in direction +A, by means of the motor  505  and gears  510 , results in rotation of the spool  560  in a second direction about an axis running through the page of  FIG. 3A , opposite to the first direction, and thus movement of the part  570  in a direction  580 B. 
     The first and second tendons  550 A,  550 B, are connected to the first and second force sensors  530 A,  530 B via the first and second tensioners  540 A,  540 B respectively. The first and second force sensors  530 A,  530 B sense the amount of force applied to each tendons  550 A,  550 B. Control of the amount of force applied to each of the first and second tendons  550 A,  550 B can be used to control the amount of movement of each of the first and second tendons  550 A,  550 B, and thus the amount of movement of the part  570  in direction  580 A or in direction  580 B. 
     The air muscle driven actuation device of  FIG. 3B  comprises an air inlet  600 ; first inlet valve  610 A; second inlet valve  610 B; first outlet valve  615 A; second outlet valve  615 B; first pressure sensor  620 A; second pressure sensor  620 B; first air muscle  630 A; second air muscle  630 B; first tendon  640 A; second tendon  640 B; a spool  650 ; and a part  660 . The air inlet  600  is connected to the first and second inlet valves  610 A,  610 B, which in turn are connected to the first and second air muscles  630 A,  630 B via the first and second pressure sensors  620 A,  620 B respectively. The first and second air muscle  630 A,  630 B are connected to the first and second tendons  640 A,  640 B respectively, which are connected to the part  660  via the spool  650 . 
     When air is provided in the first air muscle  630 A, via the first inlet valve  610 A, the first air muscle  630 A expands in direction +E and contracts in direction +C. Contraction of the first air muscle  630 A in direction +C result in the first tendon  640 A moving in direction +C and rotation of the spool  650  in a first direction about an axis running through the page of  FIG. 3B . This results in movement of the part  660  in a direction  670 A. In order to provide air to the first air muscle  630 A, the first outlet valve  615 A is closed, the second inlet valve  610 B is closed, and the second outlet valve  615 B is open. Contraction of the first air muscle  630 A in direction +C, results in extension of the second air muscle  630 B in direction −C and contraction of the second air muscle  630 B in direction −E. 
     Conversely, when air is provided in the second air muscle  630 B, via the second inlet valve  610 B, the second air muscle  630 B expands in direction +E and contracts in direction +C. Contraction of the second air muscle  630 B in direction +C result in the second tendon  640 B moving in direction +C and rotation of the spool  650  in a second direction, opposite to the first direction, about an axis running through the page of  FIG. 3B . This results in movement of the part  660  in a direction  670 B. In order to provide air to the second air muscle  630 B, the second outlet valve  615 B is closed, the first inlet valve  610 A is closed, and the first outlet valve  615 A is open. Contraction of the second air muscle  630 B in direction C, result in extension of the first air muscle  630 A in direction −C and contraction of the first air muscle  630 A in direction −E. 
     The first and second air muscles  630 A,  630 B are connected to the first and second pressure sensor  620 A,  620 B respectively. The first and second pressure sensor  620 A,  620 B sense the amount of air pressure applied to each air muscle  630 A,  630 B. The amount of air pressure applied to each air muscle  630 A,  630 B is modulated by the first and second inlet valves  610 A,  610 B, and the first and second outlet valves  615 A,  615 B. Control of the amount of air pressure applied to each air muscle  630 A,  630 B can be used to control the amount of movement of each of the first and second tendons  640 A,  640 B, and thus the amount of movement of the part  660  in direction  670 A or in direction  670 B. 
     The parts  570  and  660 , may represent, for example, one of the finger or thumb digits  102 ,  104 ,  106 ,  108 ,  110  of the hand section  10 , such as the distal finger part  112 , or proximal thumb part  132  of  FIG. 2 . In this case, the spools  560 ,  650 , represent the distal finger joint  118  and (one of) the proximal thumb joint  138  respectively. The parts  570  and  660 , may also represent, for example, one of the other parts of the hand section  10 , for example the palm section  150  of  FIG. 2 , in which case the spools  560 ,  650  may represent first wrist joint  142 . In addition, parts  570  and  660 , may also represent, for example, the third finger digit  106  of  FIG. 2 , in which case the spools  560 ,  650  may represent first palm joint  124 . 
     The motor driven actuation device of  FIG. 3A  is advantageous over the air muscle driven actuation device of  FIG. 3B . This is because in order to move the part  570 , the motor driven actuation device only requires one motor  505  and one set of gears  510 , whereas in order to move the part  660 , the air muscle driven actuation device requires two air muscles  630 A,  630 B and four valves  610 A,  610 B,  615 A,  615 B. Consequently, the air muscle driven actuation device is larger than the motor driven actuation device. In addition, the motor driven actuation device is capable of providing more accurate movement for the part  570  than the air muscle driven actuation device. 
     Each joint of the robotic hand section  10  requires its own actuation device in order to actuate that joint. For example, in the hand section  10  illustrated in  FIG. 2 , each finger digit  102 ,  104 ,  106 ,  108  requires four actuation devices, and the thumb digit  110  requires five actuation devices. In addition, the palm section  150  requires two actuation devices, and the wrist  140 ,  142  requires two actuation devices. In total, the hand section  10  illustrated in  FIG. 2  requires twenty five actuation devices. 
     Different arrangements of the hand section may require a different number of actuation devices. For example, the palm section  150  may not be required to move, or may only be required to have limited movement, in which case both of, or one of, the joints  124 ,  126  may not be required, resulting in fewer actuation devices. 
     In addition, a human finger digit, in most instances, is not capable of moving the distal finger part  112 , without also moving the middle finger part  114 . Consequently, in order to realistically mimic a human hand, the distal finger joint  118  and middle finger joint  120  may be actuated together, as described with reference to  FIGS. 4A and 4B  below. In this instance, each finger digit  102 ,  104 ,  106 ,  108  would require three actuation devices, and the hand section  10  illustrated in  FIG. 2  requires only twenty one actuation devices. 
       FIG. 4A  illustrates schematically a first arrangements for connecting a distal finger joint  118  and a middle finger joint  120  for actuation together. Although not illustrated in  FIGS. 4A and 4B , a distal finger part is connected to the distal finger joint, the distal finger joint  118  and a middle finger joint  120  are connected by a middle finger part, and the middle finger joint  120  and proximal finger joint  122  are connected by a proximal finger part. 
     As can be seen in  FIG. 4A , a first end of an extend tendon  202  is connected to the middle finger joint  120  at middle connection point  120 A. A second end of the extend tendon  202 , opposite to the first end of the extend tendon  202 , is connected to an actuation device (not illustrated). A first end of a loopback tendon  204  is connected to the distal finger joint  118  at distal connection point  118 A. A second end of the loopback tendon  204 , opposite to the first end of the loopback tendon  204 , is provided with a loopback tendon nodule  122 A. A biasing device  208 , in one embodiment a spring, is provided on the loopback tendon  204  between the loopback tendon nodule  122 A and point  204 . The loopback tendon nodule  122 A and the biasing device  208  are provided in a channel (not illustrated). Finally, a first end of a flex tendon  206  is connected to the distal finger joint  118  at distal connection point  118 A. A second end of the flex tendon  206 , opposite to the first end of the flex tendon  206 , is connected to the actuation device (not illustrated). 
     The extend tendon  202  and the flex tendon  206  may be guided through, or around the proximal finger joint  122 , so as not to hamper movement of the proximal finger joint  122 . The extend tendon  202  and the flex tendon  206  are not connected to the proximal finger joint  122 . In addition, the flex tendon  206  is not connected to the middle finger joint  120 . 
     Activation of the actuation device to which the extend tendon  202  and flex tendon  206  are connected results in the distal finger part moving about the distal finger joint  118  and the middle finger part moving about middle finger joint  120 , such that the finger digit bends or straightens. 
     In order to bend the finger digit, the flex tendon  206  is pulled in direction +A resulting in the distal finger part (not illustrated) moving about the distal finger joint  118 . In addition, the loopback tendon  204  is pulled in direction −A, resulting in the loopback tendon nodule  122 A being pulled along the channel (in direction −A) compressing the biasing device  208 . Since the distal finger joint  118  is connected to the middle finger joint  120  by a middle finger part, movement of the distal finger joint  118 , results in movement of the middle finger part, resulting in movement of the middle finger joint  120 , ultimately bending the finger digit. 
     In order to straighten the finger digit, the extend tendon  202  is pulled in direction +A, resulting in movement of the middle finger joint  120 . Since the distal finger joint  118  is connected to the middle finger joint  120  by a middle finger part, movement of the middle finger joint  120 , results in movement of the distal finger joint  118 . In addition, the loopback tendon  204  is moved in direction +A and the biasing device  208  is released, ultimately straightening the finger digit. 
     The biasing device  208  biases the finger digit in the straight position (illustrated in  FIG. 4A ) and helps to straighten the finger digit after bending. 
       FIG. 4B  illustrates schematically a second arrangements for connecting a distal finger joint  118  and a middle finger joint  120  for actuation. As can be seen in  FIG. 4B , a first end of an extend tendon  202  is connected to the distal finger joint  118  at distal connection point  118 A. A second end of the extend tendon  202 , opposite to the first end of the extend tendon  202 , is connected to the actuation device (not illustrated). A first end of a loopback tendon  204  is connected to the distal finger joint  118  at distal connection point  118 A. A second end of the loopback tendon  204 , opposite to the first end of the loopback tendon  204 , is provided with a loopback tendon nodule  122 A. A biasing device  208 , in one embodiment a spring, is provided on the loopback tendon  204  between the loopback tendon nodule  122 A and point  204 . The loopback tendon nodule  122 A and the biasing device  208  are provided in a channel (not illustrated). Finally, a first end of a flex tendon  206  is connected to the distal finger joint  118  at distal connection point  118 A. A second end of the flex tendon  206 , opposite to the first end of the flex tendon  206 , is connected to the actuation device (not illustrated). 
     The extend tendon  202  and the flex tendon  206  may be guided through, or around the proximal finger joint  122 , so as not to hamper movement of the proximal finger joint  122 . The extend tendon  202  and the flex tendon  206  are not connected to the proximal finger joint  122 . In addition, the extend tendon  202  and the flex tendon  206  are not connected to the middle finger joint  120 . 
     Activation of the actuation device to which the extend tendon  202  and flex tendon  206  are connected results in the distal finger part moving about the distal finger joint  118  and the middle finger part moving about middle finger joint  120 , such that the finger digit bends or straightens. 
     In order to bend the finger digit, the flex tendon  206  is pulled in direction +A resulting in the distal finger part (not illustrated) moving about the distal finger joint  118 . In addition, the loopback tendon  204  is pulled in direction −A, resulting in the loopback tendon nodule  122 A being pulled along the channel (in direction −A) compressing the biasing device  208 . Since the distal finger joint  118  is connected to the middle finger joint  120  by a middle finger part, movement of the distal finger joint  118 , results in movement of the middle finger part, resulting in movement of the middle finger joint  120 , ultimately bending the finger digit. 
     In order to straighten the finger digit, the extend tendon  202  is pulled in direction +A, resulting in movement of the distal finger joint  118 . Since the distal finger joint  118  is connected to the middle finger joint  120  by a middle finger part, movement of the distal finger joint  118 , results in movement of the middle finger joint  120 . In addition, the loopback tendon  204  is moved in direction +A and the biasing device  208  is released, ultimately straightening the finger digit. 
     The biasing device  208  biases the finger digit in the straight position (illustrated in  FIG. 4B ) and helps to straighten the finger digit after bending. 
     The connecting arrangements of  FIGS. 4A and 4B  can utilise either a motor driven actuation device, such as illustrated in  FIG. 3A , or an air muscle driven actuation device, such as illustrated in  FIG. 3B . 
     The connecting arrangement of  FIG. 4B  is advantageous over the connecting arrangement of  FIG. 4A , since the extend tendon  202  and the flex tendon  206  of  FIG. 4B  are required to move substantially the same distance in order to bend and straighten the finger digit. In contrast, in the connecting arrangement of  FIG. 4A , the flex tendon  206  is required to move a substantially greater distance than the extend tendon  202  in order to bend and straighten the finger digit. The result of having both tendons  202 ,  206  moving substantially the same distance is more accurate movement control, and simpler actuation control. 
     In one embodiment, the loop back tendon  204  may be an elasticated material. In this embodiment, the biasing device  204  may not be required. 
       FIG. 5  illustrate a perspective view of one of the plurality of actuation devices provided in the control section  20  of  FIGS. 1A ,  1 B and  1 C. As stated previously, each actuation device comprises a tensioner module  300 , a sensing module  400  and an actuation module  500 . Each actuation device enables movement of one component, such as one joint of a digit, of the robotic hand section  10 , by controlling movement of a flex tendon  250  and an extend tendon  255 . Although not illustrated the flex tendon  250  and extend tendon  255  may be connected to any joint of the robotic hand section  10 . 
       FIG. 6  illustrates a side view of the actuation device of  FIG. 5 . The casing surrounding the tensioner module  300  and the sensing module  400  has been removed in order to more clearly describe the components of the tensioner module  300  and sensing module  400 . The tendon  250  is connected to the actuation module  500  via the tensioner module  300  and the sensing module  400 . 
     In this embodiment, the actuation module  500  comprises a motor and gears. The motor and gears may be assembled as a single unit. A motor and gears are well known to a person skilled in the art and thus are not described in further detail in this application. In addition, each set of motor and gears may be provided with its own printed circuit board (PCB) for controlling the motor and gears. In the arrangement illustrated in  FIGS. 1A and 1B , the PCB is integrated onto the back of each motor. However alternative arrangements may be utilised. 
       FIG. 7  illustrates a side view of the tensioner module  300  comprising a first pulley  310 , a second pulley  320  and a third pulley  330 . The tendon  250  is routed through the tensioner module  300  around the first, second and third pulley  310 ,  320 ,  330  respectively. The tendon  250  may be connected at first end  250 A to a joint of the robotic hand section  10  (not illustrated). The tendon  250  may also be connected at a second end  250 B to the sensor module  400  (not illustrated). 
     The tensioner module  300  also comprises a tendon biasing device  350 , in one embodiment a spring. A first end  350 A of the spring is provided in a recess  360  in the tensioner module  300 , such that the first end  350 A of the spring cannot move. A second end  350 B of the spring is connected to the second pulley  320 . The second pulley  320  is provided in a curved recess  340 . The second end  350 B of the spring, and thus the second pulley  320 , is biased towards a second end  340 B of the recess  340  in order to maintain tension in the tendon  250 , keeping the tendon  250  taught. 
     In one embodiment, the first end  350 A of the spring is provided behind the tendon  250 , whilst the second end  350 B of the spring is provided in front of the tendon  250 . 
       FIG. 9  illustrates a side view of the tensioner module  300  where the second pulley  320  has moved along the recess  340  towards a first end  340 A of the recess  340 . 
       FIG. 8  illustrates a perspective view of the tensioner module  300 . As can be seen from  FIG. 8  the two (flex and extend) tendons  250 ,  255  of each joint are fed into a single tensioner module  300 . Tendon  250  is fed into side  300 A of the tensioner module  300  illustrated in  FIGS. 7 ,  8  and  9 . Tendon  255  is fed into side  300 B of the tensioner module  300 , which is a mirror image of side  300 A. 
     The tensioner module  300  is advantageous since it maintains tension in the tendons  250 ,  255 , which result in more accurate control of the joint to which the tendons  250 ,  255  are attached. 
       FIG. 10  illustrates a perspective view of the sensor module  400 . A second end  250 B of tendon  250  and a second end  255 B of tendon  255  are provided from the tensioner module  300 . 
     The sensor module  400  comprises a spool comprising a first (top half) spool  440  and a second (bottom half) spool  430 , a first side piece  450 A (not illustrated), a second side piece  450 B, a first force sensor  410 A, a second force sensor  410 B, and a connection bar  420  connecting the first and second force sensors  410 A,  410 B. The first force sensor  410 A and second force sensor  410 B may be any force sensor or strain gauge as known in the art. 
     The tendon  250  is connected to the first spool  440 , and the tendon  255  is connected to the second spool  430 .  FIGS. 13 and 14  illustrate the first and second spools  430 ,  440  in more detail.  FIG. 14  is an exploded view. As can be seen from  FIGS. 13 and 14 , the first spool  440  comprises a first groove  445 , and the second spool  430  comprises a second groove  435 . An end of the tendon  250  is trapped within the first groove  445  in order to securely fasten the tendon  250  to the first spool  440 . In one embodiment, a knot is tied in the end of the tendon  250  and glue is provided in the first groove  445 , such that the knotted end of the tendon  250  is securely fastened to the first groove  445  of the first spool  440 . The tendon  250  is then wrapped several times around the first spool  440  and routed over the connection bar  420  next to the first force sensor  410 A as illustrated in  FIG. 10 . An end of the tendon  255  is trapped within the second groove  435  in order to securely fasten the tendon  255  to the second spool  430 . In one embodiment, a knot is tied in the end of the tendon  255  and glue is provided in the second groove  435 , such that the knotted end of the tendon  255  is securely fastened to the second groove  435  of the second spool  430 . The tendon  255  is then wrapped several times around the second spool  430  and routed over the connection bar  420  next to the second force sensor  410 B as illustrated in  FIG. 10 . 
     Although first and second grooves  445 ,  435  have been described, any means for securely attaching the tendons  250 ,  255  to the first and second spools  440 ,  430  can be utilised. 
     The first and second spools  440 ,  430  are provided as two separate devices so that they can be rotated with respect to each other, in order to adjust the tension in the tendons  250 ,  255 . When the tension in the tendons  250 ,  255  has been adjusted as required, the first and second spools  440 ,  430  can be fixed in position. In one embodiment, a screw (not illustrated) may be provided through the first and second spools  440 ,  430  in order to fixed the relative positions of the first and second spools  440 ,  430 . The screw acts to lock the first and second spools  440 ,  430  so that they do not rotate with respect to each other. When the screw is loosened, the first and second spools  440 ,  430  can be rotated with respect to each other effectively tightening and loosening the tension in the tendons  250 ,  255 . 
       FIGS. 11 and 12  illustrates the sensor module  400  without second side piece  450 B and second force sensor  410 B in order to more clearly illustrate the components of the sensor module  400 . 
       FIG. 11  is a perspective view of the sensor module  400 . As can be seen in  FIG. 11 , the tendons  250 ,  255  are routed over the connection bar  420 , the tendon  250  is routed next to the first force sensor  410 A and the tendon  255  is routed next to the second force sensor  410 B (illustrated in  FIG. 10 ). Consequently, the first force sensor  410 A is capable of detecting force applied to the tendon  250 , whilst the second force sensor  410 B is capable of detecting force applied to the tendon  255 . The arrangement of the first and second force sensors  410 A,  410 B and the connection bar  420  of the sensing module  400  is advantageous since is enables the first and second force sensors  410 A,  410 B to detect force from the tendons  250 ,  255  respectively, without restricting movement of the tendons  250 ,  255 . 
       FIG. 12  is a side view of the sensor module  400  and only illustrates tendon  250 B. 
     As illustrated in  FIGS. 5 and 6  the sensor module  400  is connected to the actuation module  500 . In one embodiment, the shaft of the motor is connected to the first and second spools  440 ,  430 . 
     Referring again to  FIGS. 1A ,  1 B and  1 C, the control section  20  comprises a routing plate  700 . The routing plate  700  is also illustrated in  FIGS. 16A and 16B . The routing plate  700  provides standardised routing of the tendons from the hand section  10  to the control section  20 . In particular, the routing plate  700  provides routing for each pair of tendons associated with each joint of the hand section  10 , to the associated actuation device which will control movement of that joint. 
     The routing plate  700  is approximately square in shape, having four sides. Each side having eight grooves  710 , one groove  710  for each tendon. Each pair of tendons connecting to an actuation device, in the control section  20 . Each side of the control section  20  provided with four actuation devices. In addition, the routing plate  700  has four grooves  720  (illustrated in  FIG. 16B ) connected to four guide holes  725  at it&#39;s centre and four routing holes  730  for routing a further eight tendons. Each pair of tendons connecting to an actuation device, in the control section  20 . The centre of the control section  20  the control section  20  provided with four actuation devices. Consequently, the robotic hand of  FIGS. 1A and 1B  comprises  20  independent joints, each connected to one of twenty actuation devices. 
     The routing plate  700  is not limited to being approximately square in shape, and different shaped routing plates  700  may be utilised, such as, for example, approximately rectangular in shape, approximately hexagonal in shape, approximately circular in shape etc. 
     As can be seen in  FIGS. 1A and 1B  each pair of tendons is routed through the wrist section  140 ,  142 ,  144  and then fed to a tensioner module  300  of the actuation devices. As discussed with reference to  FIG. 2  the wrist section has two wrist joints  140 ,  142 . The first wrist joint  140  enables the hand section  10  to move about an X axis X 6 , and the second wrist joint  142  enables the hand section  10  to move about a Y axis Y 4 . The fourth Y axis Y 4  is orthogonal to the sixth X axis X 6 . The first and second wrist joints  140 ,  142  can also be seen in  FIG. 1A . 
       FIG. 15  illustrates schematically a pulley arrangement for routing the tendons of the first and second wrist joints  140 ,  142  to the actuation devices provided at the centre of the control section. Referring to  FIG. 15 , tendon  140 A is the flex tendon of the first wrist joint  140  and tendon  140 B is the extend tendon of the first wrist joint  140 . The tendon  142 A is the flex tendon of the second wrist joint  142  and tendon  142 B is the extend tendon of the second wrist joint  142 . 
     When the tendons are provided about a circular joint such as the first wrist joint  140  it is possible for the flex and extend tendons  140 A,  140 B to be moved substantially the same distance in order to flex and extend the hand section  10  about the first wrist joint  140 . However, it is difficult to make the second wrist joint  142  also a circular joint. Consequently, components  144  (illustrated in  FIG. 1A ), which have a curved outer surface, are provided in order to guide the tendons  142 A,  142 B of the second wrist joint  142 . Although components  144  do not form a perfect circle, the curved surfaces  144  are such that the flex and extend tendons  142 A,  142 B can be moved substantially the same distance in order to flex and extend the hand section  10  about the second wrist joint  142 . 
     The wrist joint arrangement is advantageous since it reduces backlash 
     Those skilled in the art will appreciate that while the foregoing has described what is considered to be the best mode and, where appropriate, other modes of performing the invention, the invention should not be limited to the specific configurations and methods disclosed in this description of the preferred embodiment. Those skilled in the art will recognise that the invention has a broad range of applications in many different types of robotics, and that the embodiments may take a wide range of modifications without departing from the inventive concept as defined in the appended claims.