A surgical cutting instrument (130, 200) for use with a computer-assisted device, the instrument comprising: a drive unit (240, 500) comprising a restraining mechanism and one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators; an end effector located at a distal end of the instrument (130, 200), the end effector comprising opposable gripping jaws and a cutting blade; a shaft between the drive unit (240, 500) and the end effector, the shaft housing one or more drive mechanisms for coupling force or torque from the drive unit (240, 500) to the end effector; a garage for housing the cutting blade when the cutting blade is not in use; and a control unit; wherein to perform a cutting operation, the control unit is configured to: extend, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade from a first position to a second position; retract, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade from the second position to a third position between the first and second positions; and further retract, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade to the first position; wherein: while the cutting blade is not in use, the cutting blade is maintained in the first position using the restraining mechanism or both the restraining mechanism and force or torque applied by the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators; a first magnitude of force or torque limits enforced for the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators when the cutting blade is being extended is greater than a second magnitude of the force or torque limits when the cutting blade is being retracted and further retracted; and a difference between the first and second magnitudes is based on a force or torque applied by the restraining mechanism. a drive unit (240, 500) comprising a restraining mechanism and one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators; an end effector located at a distal end of the instrument (130, 200), the end effector comprising opposable gripping jaws and a cutting blade; a shaft between the drive unit (240, 500) and the end effector, the shaft housing one or more drive mechanisms for coupling force or torque from the drive unit (240, 500) to the end effector; a garage for housing the cutting blade when the cutting blade is not in use; and a control unit; wherein to perform a cutting operation, the control unit is configured to: extend, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade from a first position to a second position; retract, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade from the second position to a third position between the first and second positions; and further retract, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade to the first position; extend, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade from a first position to a second position; retract, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade from the second position to a third position between the first and second positions; and further retract, using the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators, the cutting blade to the first position; wherein: while the cutting blade is not in use, the cutting blade is maintained in the first position using the restraining mechanism or both the restraining mechanism and force or torque applied by the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators; a first magnitude of force or torque limits enforced for the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators when the cutting blade is being extended is greater than a second magnitude of the force or torque limits when the cutting blade is being retracted and further retracted; and a difference between the first and second magnitudes is based on a force or torque applied by the restraining mechanism. while the cutting blade is not in use, the cutting blade is maintained in the first position using the restraining mechanism or both the restraining mechanism and force or torque applied by the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators; a first magnitude of force or torque limits enforced for the one or more motors, solenoids, servos, active actuators, hydraulic actuators, or pneumatic actuators when the cutting blade is being extended is greater than a second magnitude of the force or torque limits when the cutting blade is being retracted and further retracted; and a difference between the first and second magnitudes is based on a force or torque applied by the restraining mechanism.