Twisted string actuator systems

A robotic finger assembly comprising:

• a finger skeleton with a pair of pulleys having a common axis of rotation, each pulley having a non-circular shape;
• a motor for generating rotary motion of a rotor;
• first and second twisted string actuators each including a twisted string coupled at one end to the rotor and attached at an opposite end to one of the non-circular pulleys, the twisted string actuators being configured to operate in an antagonistic manner such that one twisted string actuator lengthens the twisted string of that twisted string actuator while the other twisted string actuator shortens the twisted string of that twisted string actuator in response to rotary motion produced by the motor, wherein the non-circular shape of the pulleys is adapted to keep both twisted strings in tension throughout a range of the rotary motion produced by the motor.

A twisted string actuator system comprising:

• a motor for generating rotary motion of a rotor;
• a pair of cams having a common axis of rotation, each cam having a non-circular shape;
• first and second twisted string actuators each including a twisted string coupled at one end to the rotor and attached at an opposite end to one of the non-circular cams, the twisted string actuators being configured to operate in an antagonistic manner such that one twisted string actuator lengthens the twisted string of that twisted string actuator while the other twisted string actuator shortens the twisted string of that twisted string actuator in response to rotary motion produced by the motor, wherein the non-circular shape of the cams is adapted to keep both twisted strings in tension throughout a range of the rotary motion produced by the motor.