Robot joint static torque calculator
A first pass at the load. Estimate gravity torque for a point payload on a horizontal lever and the corresponding ideal motor torque through a gearbox.
- Static joint torque
- 5.88399 N·m
- Motor torque for static load
- 0.735499 N·m
Calculations run in your browser. No account or upload required.
How to use this calculator
- Enter point payload mass in kilograms and perpendicular lever arm in metres.
- Enter motor revolutions per output revolution and gearbox efficiency.
- Use the static result as one input to a full joint-load calculation.
Formula & convention
Joint torque = m × g × perpendicular lever arm. Motor torque = joint torque ÷ (reduction ratio × efficiency). g = 9.80665 m/s².
Worked example
A 2 kg point payload at 0.3 m requires 5.88399 N·m static joint torque. With 10:1 reduction and 80% efficiency, motor torque is approximately 0.7355 N·m.
Assumptions & limits
A static point-load estimate only. Does not include link mass, inertia, acceleration, friction, shock, duty cycle, brake loads or thermal limits. It does not select or certify an actuator. Use the perpendicular distance to gravity, then perform a complete dynamics and hardware analysis.