An exoskeleton comprising: a first support configured to be coupled to a wearer of the exoskeleton ; a second support configured to be coupled to the wearer; a joint connecting the first and second supports , wherein the joint is configured to allow relative rotation between the first and second supports ; and an actuator configured to cause relative rotation between the first and second supports at the joint , the actuator including: a motor ; a ball screw coupled to the motor ; a ball nut coupled to the ball screw ; and a yoke coupled to the ball nut , wherein the motor is configured to cause rotation of the ball screw , the ball screw is configured to cause translation of the ball nut along the ball screw during rotation of the ball screw , and the ball nut is configured to cause translation of the yoke during translation of the ball nut; and a linkage coupled to the yoke , and a joint crank coupled to the linkage , wherein the yoke is attached to the ball nut and is configured to act as a translation slider to cause movement of the linkage during translation of the yoke , and the joint crank is configured such that movement of the linkage causes rotation of the joint crank about the joint , thereby causing relative rotation between the first and second supports at the joint . a first support configured to be coupled to a wearer of the exoskeleton ; a second support configured to be coupled to the wearer; a joint connecting the first and second supports , wherein the joint is configured to allow relative rotation between the first and second supports ; and an actuator configured to cause relative rotation between the first and second supports at the joint , the actuator including: a motor ; a ball screw coupled to the motor ; a ball nut coupled to the ball screw ; and a yoke coupled to the ball nut , wherein the motor is configured to cause rotation of the ball screw , the ball screw is configured to cause translation of the ball nut along the ball screw during rotation of the ball screw , and the ball nut is configured to cause translation of the yoke during translation of the ball nut; and a linkage coupled to the yoke , and a joint crank coupled to the linkage , wherein the yoke is attached to the ball nut and is configured to act as a translation slider to cause movement of the linkage during translation of the yoke , and the joint crank is configured such that movement of the linkage causes rotation of the joint crank about the joint , thereby causing relative rotation between the first and second supports at the joint . a motor ; a ball screw coupled to the motor ; a ball nut coupled to the ball screw ; and a yoke coupled to the ball nut , wherein the motor is configured to cause rotation of the ball screw , the ball screw is configured to cause translation of the ball nut along the ball screw during rotation of the ball screw , and the ball nut is configured to cause translation of the yoke during translation of the ball nut; and a linkage coupled to the yoke , and a joint crank coupled to the linkage , wherein the yoke is attached to the ball nut and is configured to act as a translation slider to cause movement of the linkage during translation of the yoke , and the joint crank is configured such that movement of the linkage causes rotation of the joint crank about the joint , thereby causing relative rotation between the first and second supports at the joint . <EOS>