A frequent question that is asked about robots is how much force they can push with. General specifications of the robot only rate the allowable payload that can be lifted, but not pushed with. However, there are some requirements and general guidelines for a robot’s pushing capability. A GP12 robot is used for the examples.

Requirements for Pushing Motions

• Shock sensor sensitivity may need to be decreased for the pushing motion to not trigger a collision detect. The end user is responsible for considering this in their risk assessment.
• The pushing force must be applied directly in line with the center of the T-Flange. Forces that are offset from the center of the T-Flange require further analysis by Yaskawa.

Unloaded Robot (No Tool)

• Guideline:
  • A robot with no tool can push with a force equivalent to maximum payload, without posture limitations
• Explanation:
  • If the robot can lift a maximum payload (force), then the robot can also push with that maximum payload when fully unloaded without any posture restriction. The reasoning for this is that if the robot can statically apply a torque to hold a force as a payload, then the motor torque is sufficient when that force is instead pushed back as a torque to the motor.
• Example:
  • If a GP12 can lift 12 kg (118 N), then it can push up to 12 kg (118 N).

Loaded Robot

• Guideline:
  • A robot with a tool can push with a force equal to maximum payload minus tool weight, without posture limitations
• Explanation:
  • A pushing force must remain below the maximum payload of the robot. So, if the robot does have a tool attached, the payload (force) + pushing force must be below the maximum payload of the robot for it to work in all postures.
• Example:
  • If the GP12 has a 4 kg (39 N) tool, then it can only push up to 8 kg (78 N) without restrictions.
  • This keeps total force on the robot below 12 kg (118 N).

Pushing Directly Downward

• Guideline:
  • When only pressing directly downward on an object, a robot can push with a force equal to maximum payload plus tool weight
• Explanation:
  • Consider the robot has a tool and tried to push downward against the floor. As the robot pushes down, the weight of the tool would eventually be fully supported by the floor (meaning the robot sees zero payload). The robot can then continue to push down until it reaches its maximum payload. The floor now receives the weight of the tool and an additional robot pushing force.
• Example:
  • If the GP12 has a 4 kg (39 N) tool and pushes an additional 12 kg (118N), then the floor could see a force of up to 16 kg (157 N).
  • The maximum possible downward force of a GP12 would be 24 kg (236 N). This assumes the robot has a 12 kg tool and pushes an additional 12 kg of force downward.