Stewart Platform
A platform with 6 degrees of freedom
High-precision parallel positioning system
A Stewart platform is a parallel kinematic structure comprising a moving platform connected to a fixed platform by six linear actuators operating in synchronisation.
This design allows an object placed on the moving platform to be moved with six degrees of freedom (DOF). In other words, the hexapod can move an object along the three translational axes (Tx, Ty, Tz) and the three rotational axes (Rx, Ry, Rz); all combinations are possible.
This technology, which stems from mechatronics, is particularly well suited to applications requiring precise, complex positioning along several axes within any given coordinate system. Consequently, an object placed on the movable platform can be positioned, adjusted and assembled simply and easily.
STEWART PLATFORM VS ROBOTIC ARM
Although these two positioning solutions are often compared within the industry, they do, however, have many differences and are designed to meet specific needs.
| Requirements | Stewart Platform | Robotic Arm |
| Degrees of freedom | 6DOF simultaneous (Tx, Ty, Tz, Rx, Ry, Rz) | Independent stacked axes |
| Stiffness | Very high (closed structure) | Lower (overlapping axes) |
| Footprint | Compact and integrated (stacked axes) | Larger (stacked axes) |
| Precision | Excellent repeatability | Cumulative errors of the axes |
| Kinematics | Parallel | Serial |
STEWART PLATFORM & ROBOTIC ARM: A HYBRID ARCHITECTURE
Combining a robotic arm with a Stewart platform brings together the best of both worlds: the reach and speed of a serial robot with the precision and rigidity of a parallel mechanism.
The arm ensures rapid overall positioning, whilst the platform carries out micrometric adjustments and orientation corrections in real time. This kinematic complementarity paves the way for high value-added applications: precision machining, optical calibration, high-tolerance assembly, adaptive polishing, and automated inspection.
Thanks to this hybrid architecture, the robotic cell gains in precision, flexibility and responsiveness, whilst reducing calibration times and improving process quality.
STEWART PLATFORM VS STAGES
Two approaches to multi-axis positioning: the parallel kinematics of the Stewart platform versus the stacking of conventional translation and rotation axes.
| Requirements | Stewart Platform | Rotary/Linear Stages |
| Architecture | Parallel kinematics (6 simultaneous actuators) | Overlapping axes (X, Y, Z, Rx, Ry, Rz) |
| Footprint | Compact, low center of gravity | Voluminous (axis accumulation) |
| Dynamic stiffness | Excellente (structure fermée) | Degraded by stacking |
| Payload | Distributed between 6 actuators | Supported by the bottom axis |
| Accuracy | Coupled movements, no error accumulation | Cumulative axis errors |
| Response time | Fast (6 simultaneous DOF) | Sequential or synchronized |
| Control Complexity | Real-time inverse kinematics | Direct control per axis |
STEWART PLATFORM & STAGES: MAXIMUM FLEXIBILITY
Combining a Stewart platform with translation and rotation stages provides a comprehensive solution for demanding applications requiring both a long stroke and exceptional precision.
The translation stages provide large linear movements, whilst the platform delivers micrometric precision and multi-axis rotation capabilities. This configuration optimises the working space whilst maintaining maximum rigidity and unrivalled positioning repeatability.
This modular architecture is used in the fields of dimensional metrology, precision optical alignment, aerospace test benches, and all environments where high-precision 6-axis positioning is required across large working areas.
Expertise recognized worldwide
a turnkey solution
Every Symétrie Stewart Platform comes with all the components required for immediate deployment: a complete mechatronic system, a dedicated controller and integrated control software.
STEWART PLATFORM
CONTROLLER
SOFTWARE
Discover our range of precision positioning hexapods for loads ranging from a few grams to several tonnes.
Our hexapod motion systems are used as dynamic test rigs capable of generating trajectories at speeds of 1 m/s and accelerations of 1 g.
From feasibility studies to maintenance, Symétrie draws on its expertise in dynamics and positioning to offer you the best solutions.
