Contactless Gravity Compensation for Precision Mechatronics

What is Gravity Compensation?

In many high-precision machines — like robotic arms, semiconductor stages, or inspection platforms — one often utilizes a part that moves vertically. However gravity constantly pulls it down.

This means your motors or actuators are always working, even just to hold the part still. That leads to:

• Unnecessary energy consumption.
• Heat generation that cause unwanted thermal expansion and distortion.
• Lager size connection wires.
• Wear and tear on components.
• Unwanted stiffness that reduces responsiveness and leads to extra position errors.
• Gravity-induced sagging.
• Adding on fail safes, for when the vertical actuator shuts down.

To make your system more efficient, stable, and accurate, you want the moving part to feel weightless. That’s exactly what gravity compensation does.

Gravity compensation is a technique used to neutralize the weight of a moving object — particularly in vertical motion systems.

Why not use springs or traditional actuators?

Traditional solutions like springs or preload structures introduce limitations — such as friction, mechanical wear, and nonlinear behaviour, drawbacks per method are:

How can our Magnetic Gravity Compensator Series help?

If you have a vertical moving part that needs to feel weightless — so it can move fast and accurately, without wasting energy, generating heat, or adding stiffness, our MSG Series can help.

The MGC series achieves this by creating a passive magnetic force that exactly balances the weight of the moving part. The result: your system performs like it’s floating on air, with minimal effort.

The technique behind the MGC Series

The MGC Series uses a combination of permanent magnets and optional lorentz coils to generate two separate forces:

Passive Bias Force (Anti-Gravity Magnet Force)

• Two magnetic assemblies generate a continuous force with extremely low parasitic stiffness in DOF6.
• This contactless magnetic field creates a constant upward force, exactly tuned by design to compensate for the weight of the moving mass.
• This eliminates direct mechanical couplings and prevents vibration transmission.
• This force requires no electrical power and introduces minimal stiffness as the coil portion is situated in the static part.

Active Z-Control Force (Only in A-models)

• A Lorentz coil provides a precise control force in the vertical direction which is added to the passive bias force.
• This enables a fast and dynamic response to external disturbances.
• Without adding heat or stiffness to the moving part.

Optimized design

• The coils and static magnet assembly form an efficient thermal path. This is beneficial for high force density.
• No moving wires = ultra-high reliability
• Durable, no mechanical wear points
• Optional water cooling can be used for additional heat dissipation.
• Both Bias Force and Lorentz Force work on the same part.

This gives you stable support and precision motion in a compact, reliable form. Without the complexity of full active levitation systems.

What makes the MGC Unique?

Unlike conventional actuators or magnetic bearings, the MGC separates gravity compensation from dynamic force control. As mentioned above: a passive bias force is created using dual magnet assemblies to balance weight without power or heat. A separate Lorentz coil then adds any required Z-axis actuation.

Key advantages include:

• Contactless operation with low stiffness
• Energy-efficient: no coil current required to counteract gravity
• No thermal load on the moving part
• Reliable in any orientation, Z and radial axis force support
• Zero energy loss in static operation
• Low parasitic stiffness (30–6000 N/m depending on model)
• Vacuum-compatible design options available.
• Suitable for 6-DOF applications: The radial clearance allows for controlled movements in six degrees of freedom, ideal for complex mechatronic applications.