Automotive switchgear controls testing systems

Case study

Automotive switchgear toggle/rocker/push-button switch testing development

Rotational torque to turn measurement of an automotive mirror selection control

Solution

Software-controlled force tester
Software-controlled torque tester
Fixtures to engage and rotate mirror controls, depress toggle and rocker switches

Benefits

Ability to implement automotive OEM internal test standards
Flexibility to evaluate ergonomic feedback characteristics
Force and torque measurement capability for any control design
Evaluation of physical and electrical switching performance interaction

Requirement

Automotive electrical systems suppliers to OEM manufacturers are tasked with meeting extensive quality and performance standards to remain high tier providers. Warranty repairs and recalls for small, relatively inexpensive components can reflect badly on the brand and suppliers may be liable for covering these sorts of costs. In addition to build quality, tactile interior controls must operate with positive feel and clear indication that they have performed the function as expected.

The powered window and external mirror control assembly, sited on the vehicle arm rest or door card is a panel which contains both push-button or toggle switches and rotary knobs to control these functions.

A tier-1 auto supplier required a flexible solution to test the force and torque characteristics of multiple switches and controls, assembled to a variety of trim and fascia panel designs.

Solution

Mecmesin supplied a Multitest compression tester and a Vortex torque tester to handle the push and twist type controls. A selection of adjustable fixtures enabled the panels to be located on the systems and accurately aligned with each upper grip used to activate the control. The two motorised, software-driven systems allowed the supplier to implement the internal OEM test standard methods as required. Mecmesin supplied a Multitest compression tester and a Vortex torque tester to handle the push and twist type controls. A selection of adjustable fixtures enabled the panels to be located on the systems and accurately aligned with each upper grip used to activate the control. The two motorised software-driven systems allowed the supplier to implement the internal OEM test standard methods as required. The software supports ‘Event Input’ signal detection at the open/close event of the switch. The hysteresis of the switch indicates the lag or offset of the actuation and release points as the circuit is opened or closed. By recording these significant points and overlaying with the physical force peaks of the mechanical control, the manufacturer can gain a thorough understanding of the component's performance. These significant points can be displayed on the force graph and indicated in the results table. The motor-driven crosshead's speed can be accurately controlled; allowing contact bounce characteristics to be evaluated.

The programming environment enabled not only on-off activation force thresholds to be measured but in the case of the rotary controls, the positivity and feedback load characteristics that provide the user with detailed tactile information. The ergonomic feel of the controls is an important quality indicator and the ability to tune this aspect of the design is a valuable capability for the development team, in addition to the essential functionality and durability checking.