Dynamometer for pedelecs

Client

Brief

For the dynamic development of the pedelec market and to ensure the quality during and after the development, the bicycle manufacturer wants a dynamometer for today’s and future test and development services.
The enormous growth in the range of electric bicycles and the increased demands for its approval have generated the need for a flexible test system. Derby Cycle has specified the system as a test bench for a complete system, for a complete bicycle. The main concern was the flexibility in terms of performance and variability of the test programs. In addition, the set-up time of the test bench should be kept low in order to quickly compare different bicycle models.

Challenge

The challenge during the implementation was the selection of suitable components. A high performance of up to 2 kilowatts and a well power dissolution of an R200 reach wide test to meet were the criteria to meet. In addition, the control software should be suitable for a laboratory and experimental operation as well as for automatic programs.

EMEC has designed a platform for different performance classes based on an industrial control system from Beckhoff. The modular Plug & Play system allows flexible adaptation of the chassis dynamometer to the needs of other customers. For electric bikes, for example, the braking power reaches 2100 watts and an unwinding speed of 45 km/h. This also allows S-Pedelec to be tested right up to the performance limit. In addition, a pedal crank drive was developed, which allows a bilateral force entry. The pedal drive has been programmed so that it can reproduce a bumping behavior. To be able to test also from the children’s bike to the high-end mountain bike, the power at the pedal drive reaches up to 1400 watts and 120 Nm of torque with a maximum cadence of 150 rpm.

Thanks to a flexible clamping system, a bicycle can be equipped within a few minutes. The test and validation programs range from prefabricated tests such as the R200 range test to freely specifiable special tests. Depending on the test job, the data acquisition includes the physical parameters voltage, current consumption or temperature behavior. In addition, the entire CAN protocol can be recorded and evaluated.

Results

Derby Cycle – but also other customers are able to use the test bench to test and evaluate existing systems in the shortest possible time. In addition, new drive systems can be tested and validated in-house.
As a result, technical findings are obtained early, which are incorporated into the later series transfer. Potentials in quality management and assurance can thus be exploited directly and fully.

Quote from Derby Cycle: “Thank you for the complex implementation, I think we have jointly implemented one of the best test benches in the market”

Due to the modular design of the test bench can be extended up to a 4 × 4 system, which is flexibly adjustable in track width and axle width. Here, all roles are controlled individually, which allows a completely free variability in the functional test. In addition, the test stand variant EMC also allows the use in an EMC measuring chamber.