Abstract: An example robot includes: a leg having an upper leg member and a lower leg member coupled to the upper leg member at a knee joint; a screw actuator disposed within the upper leg member, where the screw actuator has a screw shaft and a nut mounted coaxial to the screw shaft such that the screw shaft is rotatable within the nut; a motor mounted at an upper portion of the upper leg member and coupled to the screw shaft; a carrier coupled and mounted coaxial to the nut such that the nut is disposed at a proximal end of the carrier; and a linkage coupled to the carrier, where the linkage is coupled to the lower leg member at the knee joint.

Abstract: An example robot includes movable members, a hydraulic system including at least (i) hydraulic actuators configured to operate the movable members, and (ii) a source of hydraulic fluid, and a controller. The controller may be configured to: determine a task to be performed by the robot, where the task includes a plurality of phases; cause hydraulic fluid having a first pressure level to flow from the source to the hydraulic actuators for the robot to perform a first phase of the plurality of phases of the task; based on a second phase of the task, determine a second pressure level for the hydraulic fluid; and adjust, based on the second pressure level, operation of the hydraulic system before the robot begins the second phase of the task.

Abstract: An example robot includes movable members, a hydraulic system including at least (i) hydraulic actuators configured to operate the movable members, and (ii) a source of hydraulic fluid, and a controller. The controller may be configured to: determine a task to be performed by the robot, where the task includes a plurality of phases; cause hydraulic fluid having a first pressure level to flow from the source to the hydraulic actuators for the robot to perform a first phase of the plurality of phases of the task; based on a second phase of the task, determine a second pressure level for the hydraulic fluid; and adjust, based on the second pressure level, operation of the hydraulic system before the robot begins the second phase of the task.

Abstract: A robotic system includes a body including at least one attachment mechanism configured to removably couple a modular component to the body. The modular component includes at least one movable part operable to move relative to the body when the modular component is attached to the body. The system includes a communication interface coupled to the body and configured to be communicatively coupled to the modular component to receive information relating to the modular component and operation of the at least one movable part. The system includes a control system coupled to the body and the communication interface. The control system is configured to: in response to the modular component being attached to the body, receive the information from the modular component by way of the communication interface, and operate the at least one movable part of the modular component according to the information.

Abstract: An example method includes identifying an operating state at which a velocity of a hydraulic actuator configured to operate a movable member of a robot is less than a threshold velocity and an actuator force is less than a threshold force, determining a valve command that corresponds to the operating state, such that the valve command is provided to a valve configured to control flow to and from the hydraulic actuator, and the valve includes a spool movable within a body of the valve, and the valve command causes the spool to move within the body of the valve to a position that induces the operating state, and determining a null bias signal based on the valve command.

Abstract: An example robot includes: a motor disposed within a housing at a joint configured to control motion of a member of a robot; a controller including one or more printed circuit boards (PCBs) disposed within the housing and including a plurality of field-effect transistors (FETs) disposed on a surface of a PCB of the one or more PCBs facing the motor; a rotary position sensor mounted on the controller; a shaft coupled to a rotor of the motor and extending therefrom to the controller; and a magnet mounted within the shaft at an end of the shaft facing the controller.

Abstract: An example robot includes: a motor disposed at a joint configured to control motion of a member of the robot; a transmission including an input member coupled to and configured to rotate with the motor, an intermediate member, and an output member, where the intermediate member is fixed such that as the input member rotates, the output member rotates therewith at a different speed; a pad frictionally coupled to a side surface of the output member of the transmission and coupled to the member of the robot; and a spring configured to apply an axial preload on the pad, wherein the axial preload defines a torque limit that, when exceeded by a torque load on the member of the robot, the output member of the transmission slips relative to the pad.

Abstract: An example robot includes: a leg having an upper leg member and a lower leg member coupled to the upper leg member at a knee joint; a screw actuator disposed within the upper leg member, where the screw actuator has a screw shaft and a nut mounted coaxial to the screw shaft such that the screw shaft is rotatable within the nut; a motor mounted at an upper portion of the upper leg member and coupled to the screw shaft; a carrier coupled and mounted coaxial to the nut such that the nut is disposed at a proximal end of the carrier; and a linkage coupled to the carrier, where the linkage is coupled to the lower leg member at the knee joint.

Abstract: A control system may receive sensor data indicative of respective fluid levels of two or more hydraulic accumulators configured to operate at respective target fluid levels within a hydraulic system. The control system may determine respective errors of the hydraulic accumulators based on the respective fluid levels and respective target fluid levels of the hydraulic accumulators. The respective errors may correspond to pressure errors, fluid volume errors, or other types of errors of the hydraulic accumulators.

Abstract: A control system may receive sensor data indicative of respective fluid levels of two or more hydraulic accumulators configured to operate at respective target fluid levels within a hydraulic system. The control system may determine respective errors of the hydraulic accumulators based on the respective fluid levels and respective target fluid levels of the hydraulic accumulators. The respective errors may correspond to pressure errors, fluid volume errors, or other types of errors of the hydraulic accumulators. Responsive to determining the respective errors, the control system may determine that the error of a given hydraulic accumulator is greater than errors of the other hydraulic accumulators and provide instructions to control a hydraulic valve to supply fluid from a single pump of the hydraulic system to the given hydraulic accumulator.

Abstract: An example robot includes movable members, a hydraulic system including at least (i) hydraulic actuators configured to operate the movable members, and (ii) a source of hydraulic fluid, and a controller. The controller may be configured to: determine a task to be performed by the robot, where the task includes a plurality of phases; cause hydraulic fluid having a first pressure level to flow from the source to the hydraulic actuators for the robot to perform a first phase of the plurality of phases of the task; based on a second phase of the task, determine a second pressure level for the hydraulic fluid; and adjust, based on the second pressure level, operation of the hydraulic system before the robot begins the second phase of the task.

Abstract: An example robot includes movable members, a hydraulic system including at least (i) hydraulic actuators configured to operate the movable members, and (ii) a source of hydraulic fluid, and a controller. The controller may be configured to: determine a task to be performed by the robot, where the task includes a plurality of phases; cause hydraulic fluid having a first pressure level to flow from the source to the hydraulic actuators for the robot to perform a first phase of the plurality of phases of the task; based on a second phase of the task, determine a second pressure level for the hydraulic fluid; and adjust, based on the second pressure level, operation of the hydraulic system before the robot begins the second phase of the task.