Robot the Next Generation

Toward Most Agile and Cost Effective Life-sized Robot

Robotic Legs by
Coaxial Spherical Parallel Mechanism

Power X 4

  • Each legs have four actuators on its pelvis

  • The legs use all the outputs of the four actuators in a vertical direction


Life X 64

  • Vertical, radial and lateral load on end effector is equally distributed on actuators

  • When the load is reduced to 1/4, the gear life is increased by 64 times


Light Design

  • Due to the distribution effect of the load, the size of motor and gear could be reduced.


Integrated Actuator

  • Because all the actuators are located at pelvis, the leg has lower inertia

  • Thermal management is easy as parts with a lot of heat are located at the pelvis


Simpler Solution

  • This unique mechanism have analytic solution as simple as serial link kinematics

Load Distribution

While the leg exerts force along the vertical direction,
the load from end effector is distributed equally to all four actuators.
This unique characteristics make robot 4 times stronger than its capacity.

Gear Capacity

Due to the distribution effect of the load,
the force applied to the gear is reduced to 1/4.
This has the effect of increasing the life of the reducer by 64 times.
In addition, reducing the size of the reducer allows the legs to be designed lighter.

Gear Limited GRF(Cont. Limit)

The Ground Reaction Force is the force that the end effector pushes against the ground.
It is usually limited by capacity of gears and motors.

The left figure shows maximum GRF based on continuous gear output.
The values ​​are calculated based on the product manual.

Body weight to GRF Ratio

The GRF should be evaluated relative to body weight(BW).

The designed leg have under 12 kg of mass.
Then the mechanical part of biped would have 24 kg of mass.
Including the electronics and chassis, it would weigh around 35 kg.

In this case, the continuous GRF limit exceeds BW in most areas.
Moreover, the continuous GRF limit is 2 times higher than BW in some region.

Utilization as a Bipedal Robot

This manipulator is mainly designed to be utilized as a robotic leg.
As introduced on video clips, it has 4 degrees of freedom.
If the two legs with the advantages listed above are placed side by side,
it will become an agile biped robot.


Ease of Control

Due to centralized mass distribution,
the error from difference between real robot and simplified control model could be minimized.

Because it has a simple analytical solution,
the computation time is short despite the parallel structure.

Stair Climbing

Jumping and Landing

Object Handling &
Self Driving

Wearable Transportation

Utilization as a Robot Arm

Due to the unique design,
the payload is amplified 4 times compared to using a single actuator.

Due to centralized mass distribution,
the mass of the moving part is dramatically reduced.


Maintenance

The actuator and joint can be easily disassembled by loosening the 14 bolts.
To disassemble the actuator set, you only need to loose 6 bolts.


Payload

Due to the spherical parallel mechanism,
the capacity of this robot arm exceeds 40 kg at any position.


Range of Motion

Although this manipulator has parallel structure,
it has very wide range of motion.
The blue colored region shows the workspace of this manipulator.

Questions?

Contact causeim@gmail.com to get more information about this project