Planetary candidate review
Review the exact ZHR-P model's specifications and required tests. P60 is CAN only with no native EtherCAT; confirm other model interfaces individually.
View ZHR-P model matrixHumanoid Robot Actuator Selection
Choose humanoid actuators by joint load, not peak torque alone.
Humanoid hip, knee, ankle, shoulder, elbow, and wrist joints need different actuator architectures. Use this guide to map torque density, backlash, backdrivability, interface, and package constraints to ZHR-P and ZHR-H families.
Start with the operating cycle
Compare torque at the required speed, peak duration, cooling and external loads for each axis. ZHR-P planetary and ZHR-H harmonic modules are candidates for engineering review. A joint name, gear type or peak-torque figure does not establish robot payload, impact tolerance or suitability.
Joint-by-joint mapping
Humanoid actuator architecture by joint role
| Joint area | Main constraints | Candidate family | Evidence required |
|---|---|---|---|
| Hip / knee / ankle | Contact loads, torque-speed cycle, backdrive behavior, thermal duty | Evaluate ZHR-P | Selected model's thermal, bearing and transient load limits; the family label is not shock qualification. |
| Shoulder / elbow / wrist | Loaded accuracy, lost motion, stiffness, package and routing | Evaluate ZHR-H | Loaded error and stiffness data, output bearing limits and selected ratio; qualify at system level. |
Harmonic candidate review
Review the selected ZHR-H model and reduction ratio. The published interface boundary is CAN / RS485; confirm the command set and controller compatibility.
View ZHR-H model matrixCheck the evidence
Public CAD, dimension images and catalogs help preliminary integration. Request matching revisions and test conditions before approving a configuration.
Open technical downloadsJoint-specific engineering review
Treat the checks below as inputs to a model review, not proof that a catalog actuator fits a humanoid. State which values are simulated, measured or still unknown. Use the same operating conditions when comparing candidates.
Hip actuator: separate pitch, roll and yaw cases
Prepare a separate load profile for each axis, covering single-leg stance, swing, acceleration and recovery motions. Supply robot mass, carried load, link geometry and the torque-speed-time trace; body mass alone cannot define required joint torque.
- Thermal: include repeated gait cycles and sustained stance, with the actual housing-to-structure cooling path.
- Mechanical: specify radial, axial and overturning loads at the output, and whether external bearings carry them.
- Integration: check cable bend and twist through the complete range of motion. State the required behavior after bus loss or power loss, including any holding or controlled-lowering requirement.
Review gate: obtain model-specific limits and evaluate the worst operating case before choosing a ratio or claiming a supported robot mass.
Knee actuator: include crouch, standing up and repeated stops
A walking trace alone is incomplete if the robot must crouch, rise or hold a bent-knee pose. Provide those segments with their durations, joint speeds and repetition rates. For a linkage-driven knee, include the changing transmission geometry rather than treating output torque as constant through the motion.
- Thermal: include low-speed loaded holds and recovery time between high-load segments.
- Load and power: specify contact transients separately from motor peak torque. Ask how the drive and supply handle deceleration energy.
- Integration: check wiring clearance at full flexion and service access. Define the required outcome after a stop command or power loss; do not assume the reducer or an unspecified brake will hold the pose.
RFQ addition: provide the pose sequence, linkage drawing if used, maximum permitted motion after a stop and the intended validation procedure.
Ankle actuator: evaluate contact loads and limited packaging together
Document pitch and roll requirements, foot geometry, ground-contact cases and available volume. Include the external load path from the foot to the structure; actuator torque capacity does not establish output bearing capacity or resistance to landing impacts.
- Control: state the required feedback, update rate and behavior during contact transitions. Request controller and firmware compatibility evidence.
- Heat and loads: describe the enclosed installation, cooling path, expected contact transients and repeated correction motions.
- Routing and stops: check cable clearance near the foot, travel limits and strain relief. Define what motion remains acceptable after communication or power loss.
Review gate: confirm mechanical load limits and test the installed assembly. A compact envelope or high peak-torque value alone does not qualify the ankle.
Shoulder and elbow: budget loaded positioning error
For a humanoid arm or precision robot arm, supply link lengths, tool mass, payload position and the required end-effector accuracy. Review the extended-arm hold as well as acceleration. An actuator's backlash figure is only one input to the complete arm's accuracy.
- Precision: request loaded stiffness, lost motion and repeatability conditions; include structural deflection, feedback location and thermal drift in the error budget.
- Thermal and loads: provide sustained holds, torque-speed traces and output bearing loads for the largest reach.
- Integration: check harness movement at both joints. Specify payload retention and allowed motion after a power loss; confirm whether a separate holding mechanism is needed.
Candidate: evaluate the selected ZHR-H model and ratio against these requirements; its harmonic reducer does not guarantee a particular arm payload or positioning accuracy.
Wrist actuator: balance tool offset, mass and service routing
Specify tool and gripper mass, center of gravity, working forces, wrist travel and acceleration. Include eccentric loads and tool moments rather than listing payload mass alone. State whether travel is limited or continuous and how power, data and any service lines must pass the joint.
- Package: compare overall installed mass, connector clearance, mounting details and cable bend radius, not just actuator diameter.
- Performance: request the relevant torque-speed data, bearing limits and precision data under tool load. Include heat from repeated fine motions or loaded holds.
- Stop behavior: define tool orientation and retention requirements after interruption. Do not assume hollow routing, slip rings or a brake are included.
RFQ addition: send the tool drawing and service-routing sketch, plus the required loaded accuracy and permitted travel.
Sizing reference: check torque-speed capability and thermal conditions when integrating a motor into a robot joint. See Kollmorgen's frameless motor integration guidance. This supports the general sizing method; its motor ratings and test conditions do not apply to ZHR products.
RFQ questions for humanoid actuator selection
Download the actuator inquiry checklist to prepare the inputs below and share the relevant fields with engineering.
Joint axis, robot and carried mass, link lengths and geometry
Torque-speed-time trace, peak duration, external forces and moments
Duty cycle, ambient temperature, cooling path and thermal limits
Voltage, controller, required protocol and feedback requirements
Mounting drawing, cable route, travel and installed mass target
Stop and holding behavior, sample quantity, project stage and test plan
Paste these inputs into the message field of the selected series' engineering inquiry form. Mark missing values as unknown and request a review before choosing a model. For document requests, name the required CAD, drawing, protocol manual or test data and the configuration to which it must apply.
Humanoid actuator selection FAQ
Which actuator type is best for humanoid hip and knee joints?
No actuator family is qualified by joint name alone. Compare the complete torque-speed cycle, peak duration, cooling, bearing loads, impact cases and power-loss behavior. ZHR-P is a planetary candidate for evaluation; its suitability, backdrive behavior and shock limits require model-specific evidence.
When should humanoid designers choose harmonic actuators?
Evaluate ZHR-H when reduced lost motion and packaging are important. Check loaded positioning error, stiffness, thermal drift, output bearing loads and cable routing for the selected model and ratio. Harmonic reduction alone does not establish end-effector accuracy or safe holding after power loss.
What should engineers confirm before requesting a humanoid actuator quote?
Provide the joint axis, robot and carried mass, torque-speed-time profile, external loads, cooling conditions, voltage, controller and required protocol, mounting drawing, cable route, stop and holding requirements, sample quantity and project stage. Mark unknown inputs for engineering review instead of substituting peak torque.
Need a humanoid actuator shortlist?
Share the operating profile and integration constraints for a configuration review. Suitability remains subject to model-specific evidence and validation in your assembly.
Prepare Your Engineering InquiryCompare robot arm precision and wrist integration requirements