Basic drive control
HCB-DCB (Drive Control Basic)

Electrohydraulic drive controls on mobile machines enable more flexible, sensitive driving behavior than purely hydraulic solutions. The basic drive control from Völkel enables the diesel engine, the drive pump and a hydraulic motor to be controlled and is already equipped with extensive functions. Nevertheless, the control system is designed in such a way that it is also economical for smaller machines, such as wheel loaders.

Depending on the operating mode, different characteristics such as starting behavior, acceleration, deceleration and limit values such as the final speed or the speed range of the diesel engine can be set. The range of functions is completed by the reversing mode for quickly reversing the direction of travel, a speed control, an adjustable creep speed, the inching function and a load limit controller to protect the diesel engine against overload.

The standard hardware platform for the DCB is the HCB controller. If the DCB is to be integrated into a machine control system, it can easily be ported to another Völkel hardware platform.

The functions in detail

Release and setpoint specifications

A prescribed procedure must be followed to set the machine in motion: First the diesel engine must be started, then the go-ahead is given and only then may a set value for the travel speed be generated. If this sequence is not adhered to, no control value is generated. Depending on the machine type, the setpoint can be set using a joystick or an accelerator pedal. If the machine is driven by pedal, a direction release via an FNR switch is required for forward and reverse travel.

Starting and braking behavior

The driving behavior of the machine can be set via characteristics and limit values for different operating modes. For example, the sensitivity of a setpoint generator (joystick, pedal) can be mapped linearly or reduced near the zero point and increased in the end range to enable a more sensitive start-up. Acceleration and braking ramps can be set static or dynamic. Separate speed limits can be set for each operating mode.

Speed control

When the speed control is activated, the control variables for the diesel engine, the pump and the hydraulic motor are frozen in order to maintain the speed in the open control loop at the time of activation. The speed control is active until the button is pressed again or braked.

Inching

When loading a wheel loader, it is necessary to drive at an increased diesel speed even at low speeds in order to supply the power to the lifting frame and the bucket. The diesel speed is set by the accelerator pedal depending on the driving speed. The inching pedal then reduces the driving speed again, but the diesel speed is maintained.

Creep speed

In creep speed, the final speed can be infinitely limited independently of the currently selected operating mode. The driver then has the entire pedal travel available for the limited speed range. This allows the machine to be driven even more sensitively

load limit controller

The load limit controller protects the diesel engine from “stalling” by limiting the hydraulic Power depending on the pressure of the diesel engine speed

Control unit: HCB / Application: DCB (Drive Control Basic)