Renesas and Minebea Mitsumi Collaborate on Stepping Motors

Renesas Electronics Corporation and MINEBEA MITSUMI Inc. announced the joint development of resolver-based (angle sensor) stepping motor and motor control solutions optimized for use in robots, office automation (OA) equipment, and medical/nursing care equipment. These applications require motors with higher precision motor control, miniaturized form factors, and improved resistance to environmental influences. Working in collaboration, Renesas and MinebeaMitsumi have developed resolver sensor-based stepping motors and motor control solutions that address these application requirements.

MinebeaMitsumi has a strong track record with resolver sensors for automotive applications and, for the first time, has developed a new resolver for stepping motors to be used in consumer and industrial equipment applications such as robots, OA equipment, and medical/nursing care equipment. As the global 32-bit microcontroller (MCU) market leader (Note 2), Renesas has developed a new resolver-to-digital converter (RDC) that supports MinebeaMitsumi’s new stepping motors, as well as control driver software for controlling the RDC with a 32-bit RX MCU. Renesas also provides a resolver-based stepping motor control kit, which includes development tools, including MinebeaMitsumi’s stepping motor with resolver and an evaluation board with RDC, allowing users to jump-start application development.

Features of the New Resolver-Based Stepping Motor Solutions

Stepping motors with a resolver allow high-precision motor control even in harsh environments with heat, dust, or vibration. They also deliver superlative characteristics such as the ability to carry heavy loads without step-out. Renesas and MinebeaMitsumi have developed a new type of resolver stepping motor and resolver motor control solutions that provide superlative cost performance, which makes it possible to expand the range of applications for stepping motors. For example, in robots or automated guided vehicle (AGV) development, customers can achieve high-precision motion even in harsh environments such as warehouses or the outdoors, while reducing costs and further miniaturizing industrial equipment by using smaller motors.

Key features of MinebeaMitsumi’s stepping motor with a resolver

• High torque characteristics: 2 to 3 times as much torque compared to existing products due to no step-out control
• Control characteristics: able to drive at broadband and ultra-low speeds
• Low power consumption: current optimization by servo control that responds to the actual load
• High precision: high position precision achieved by high resolution of 200,000 P/R
• Environmental resistance: highly resistant to heat, dust, and vibration due to its simple structure
• Miniaturization: the high torque of these motors makes miniaturizing application products possible

Key features of Renesas’ RDC and RDC control driver software

• Detection methods: VR-type voltage detection, VR-type current detection
• RX MCU support: Renesas supplies RDC driver software for the RX24T (support for other MCUs planned)
• Resistance to electromagnetic noise: position detection is possible with a signal-to-noise ratio of 1/2 (noise twice the signal) due to the inclusion of filters

Renesas’ resolver-based stepping motor control kit

• Included items: MinebeaMitsumi 42-mm square resolver stepping motor, control board, CPU board (includes the RDC and RX24T)
• Development support tools: Renesas Motor Workbench (includes real-time waveform display functions)
• Included software: RDC control driver software, stepping motor control software

Availability

MinebeaMitsumi plans to start sample shipments of the new resolver-based stepping motors in January 2020 with mass production starting in April 2020. Renesas’ resolver-based stepping motor control kit will be available in January 2020.

For more details on MinebeaMitsumi’s stepping motors, visit: https://www.eminebea.com/en/product/rotary/steppingmotor/resolver/

For more details on Renesas’ stepping motor with resolver control solutions, visit: https://www.renesas.com/solutions/key-technology/motor-control/resolver-solution.html