HYDAC ADSteer: a smarter steering solution for South African agriculture
HYDAC’s ADSteer boosts manoeuvrability, reduces soil and tyre wear, and simplifies steering for multi-axle agricultural trailers.
As South African agriculture continues to modernise with more advanced mechanisation and precision technologies, the need for adaptable, intelligent systems has never been more important. One such innovation is HYDAC’s ADSteer—an electro-hydraulic additional steering solution designed to enhance manoeuvrability, reduce soil and tyre wear, and simplify trailer handling for dual and triple-axle towed implements.
Designed for trailed implements
ADSteer is primarily designed for trailed agricultural equipment with either two or three axles. In a dual-axle setup, one axle is steered. In a triple-axle configuration, the middle axle is fixed while the front and rear axles are steered, allowing the trailer to pivot around a central point. This arrangement significantly improves turning performance and reduces tyre scrub and shear force on wheel hubs.
The system relies on a combination of a modular hydraulic control manifold, an electronic control unit (ECU), and several integrated sensors. A yaw rate accelerometer detects the rotational motion of the trailer, indicating the start of a turn.
Speed sensors mounted on an axle measure vehicle speed, allowing the system to determine how quickly the steered axles should respond. Angle sensors provide feedback to the ECU about the actual position of the steered axles, helping maintain control within safe steering limits. An inclinometer measures both forward/backward and lateral acceleration, ensuring that steering adjustments are appropriate for current operating conditions.
One of the key advantages of ADSteer is that it functions completely independently of the tractor’s hitch or steering system.
That’s a big benefit, explains Johan Stofberg, Project Engineer at HYDAC South Africa.
It doesn’t matter what kind of hitch is used. ADSteer operates on its own, which means it can be used across a wide variety of tractors without needing any special mechanical linkage.
Managing safety and speed
Functional safety is a central design principle in the ADSteer system. The software continuously monitors speed and motion to reduce the available steering angle at higher speeds, ensuring stability and control.
At lower speeds, typically below 10 kilometres per hour, steering angles of up to ±20 degrees are available. As speed increases, the system gradually reduces this angle, with full steering functionality disabled at around 55 kilometres per hour to avoid unsafe turning with heavy trailers.
The ECU uses pre-programmed data about the trailer's geometry, including the distance between the steered and fixed axles, to calculate the optimal steering angles. These measurements are simple to configure and are often standard for specific equipment types.
Once the trailer’s measurements are entered into the software, ADSteer handles everything from there. There’s no need for mechanical adjustments or complex setup procedures, Johan says.
In-track and crab steering development
HYDAC is also working on enhancements to ADSteer functionality, including in-track steering. In typical operations, the tractor is GPS-enabled, but the trailer is not.
With in-track steering, the trailer can follow the exact path and curvature of the tractor without needing its own GPS system. The trailer does this by following the tractor’s movements and turning dynamics.
This kind of in-track functionality will be very useful, says Joahn. It means reduced crop damage, better field efficiency, and more accurate handling—without the extra cost or complexity of installing GPS on the trailer.
Crab steering is another development under consideration. It would allow the trailer to move diagonally relative to the tractor, especially useful when working on slopes. This reduces the risk of sideways slipping and offers improved stability for equipment like planters, which often operate on uneven or inclined terrain.
A modular, scalable system
The ADSteer system integrates into HYDAC’s Hydraulic Implement Control (HIC) block, which is modular by design. This means that additional hydraulic functionality—such as a spreader drive or extra valves—can be stacked onto the existing system. It allows the trailer to serve multiple purposes without compromising the steering function.
Steering itself requires minimal hydraulic flow—between seven and twenty-five litres per minute—making it possible to prioritise flow to steering functions for safety while supplying other components with secondary flow as needed.
ADSteer is also ISOBUS-compatible, allowing for easy integration into modern tractors. Where ISOBUS is not available, HYDAC offers its own display options. Functionality is the same on either platform, with layout differences tailored to user preferences.
Eliminating manual steering adjustments
One of the most practical benefits of ADSteer is the removal of manual steering adjustments, Mr Stofberg highlights.
Many South African farmers currently rely on manually/mechanically actuated steering cylinders to adjust trailer direction. ADSteer replaces this with an automated system that uses real-time data and electronic control to determine the optimal steering angle.
Powered by the tractor’s Power Beyond port, the system maintains a continuous hydraulic flow that enables on-the-fly steering corrections.
It’s a huge improvement, notes Mr Stofberg. There’s no need for manual input. The trailer just follows the terrain and the tractor’s movement seamlessly.
A local pilot and looking ahead
HYDAC South Africa is preparing to launch a pilot project with a Johannesburg-based OEM to validate the system under local conditions. This real-world trial will help refine sensor integration, assess compatibility with local axles, and fine-tune the system for the South African market.
Our goal is to offer a fully supported, locally relevant solution, concludes Johan. ADSteer isn’t just a smart product—it’s a long-term platform that fits perfectly with the shift toward smarter, safer, and more efficient agriculture in South Africa.
