Kinetic and dimensional optimization for a tendon-driven gripper

A robotic system, comprising:

• a palm;
• a first finger including a first proximal finger element pivotally coupled to the palm at a first proximal joint and a first distal finger element pivotally coupled to the first proximal finger element at a first distal joint;
• a second finger including a second proximal finger element pivotally coupled to the palm at a second proximal joint and a second distal finger element pivotally coupled to the second proximal finger element at a second distal joint;
• a first extensor element physically coupled to bias the first finger into a spaced apart configuration, wherein the first extensor element includes a first proximal torsional spring at the first proximal joint and a first distal torsional spring at the first distal joint;
• a second extensor element physically coupled to bias the second finger into a spaced apart configuration, wherein the second extensor element includes a second proximal torsional spring at the second proximal joint and a second distal torsional spring at the second distal joint;
• a first flexor element physically coupled to actuate the first finger into a closed configuration in response to an application of a first actuation force to the first flexor element;
• and
• a second flexor element physically coupled to actuate the second finger into a closed configuration in response to an application of a second actuation force to the second flexor element;
• wherein the first distal finger element has a first gripping surface, the second distal finger element has a second gripping surface, and the first and the second distal finger elements are constrained such that, in response to application of the first actuation force to the first flexor element and application of the second actuation force to the second flexor element, the first and the second gripping surfaces remain parallel to one another along an entire range of movement when the first and the second proximal finger elements are not in contact with an object to be grasped, and the first and the second distal finger elements passively rotate toward one another when at least one of the first or the second proximal finger elements is in contact with the object to be grasped.

A method of actuating a robotic gripper, comprising:

• applying a first parallel closing force to a first flexor element of a robotic gripper and applying a second parallel closing force to a second flexor element of the robotic gripper, wherein the robotic gripper includes a first proximal finger element pivotally coupled to a palm, a second proximal finger element pivotally coupled to the palm, a first distal finger element pivotally coupled to the first proximal finger element at a first distal joint, and a second distal finger element pivotally coupled to the second proximal finger element at a second distal joint, wherein:
• upon applying the first parallel closing force to the first flexor element and applying the second parallel closing force to the second flexor element, the first distal finger element and the second distal finger element remain parallel to one another along an entire range of movement as the robotic gripper closes and the first proximal finger element and the second proximal finger element are not in contact with an object to be grasped;
• and
• applying a first enveloping force to the first flexor element and applying a second enveloping force to the second flexor element, wherein:
• upon applying the first enveloping force to the first flexor element and applying the second enveloping force to the second flexor element, the first distal finger element and the second distal finger element passively rotate toward one another as the robotic gripper closes and at least one of the first or the second proximal finger elements is in contact with the object to be grasped.

A robotic gripper system, comprising:

• a kinematic assembly including a first finger assembly, a second finger assembly, a proximal assembly having a recess including a plurality of grooved coupling features, a first flexor tendon coupled to the first finger assembly to actuate the first finger assembly to move with respect to the proximal assembly, and a second flexor tendon coupled to the second finger assembly to actuate the second finger assembly to move with respect to the proximal assembly;
• and
• a motor pack including an actuation piston fitting for engaging with the plurality of grooved coupling features, an engagement ring for interfacing with the proximal assembly, and a motor for actuating the piston fitting to move with respect to the engagement ring;
• wherein when the actuation piston fitting is engaged with the plurality of grooved coupling features, the engagement ring is interfaced with the proximal assembly, and the piston fitting is actuated by the motor to move with respect to the engagement ring, the piston fitting causes the first flexor tendon to actuate the first finger assembly to move with respect to the proximal assembly and the piston fitting causes the second flexor tendon to actuate the second finger assembly to move with respect to the proximal assembly.