FEATURE MOTION CONTROL
SELECTING A STEPPER
MOTOR WITH CONFIDENCE To get the best results from a stepper
motor, it’s important to match the motor to the job. Dave Walsha, director of sales and marketing at EMS, offers his guidance
S
tepper motors are at the heart of precision motion control, powering everything from robotics to medical devices. Unlike
traditional motors that spin continuously, these divide a full rotation into a series of precise, equal steps. Making incremental movements instead of continuous ones means stepper motors operate with a high degree of accuracy without the need for feedback systems such as encoders.
CONSIDERATIONS A stepper motor can be the preferable option for applications where repeatability and precision are more important than high speed. Even at lower speeds, these will deliver strong torque, but crucially often don’t require extra gearing. This enables a simpler design, faster response times and often quieter operation. When selecting a stepper motor, design engineers will first need to assess their torque requirements. This is especially important in applications where the motor needs to hold a position against an external force, like in a vertical lift or robotic arm. If the holding torque isn’t sufficient, the load may drift or fall out of position when the motor isn’t moving. Assessing the running torque, while the motor is in motion, is also important. Running torque decreases as speed increases, which may impact output if the stepper motor isn’t suitable for its application. Imagine a robotic arm lifting and moving objects. As the arm extends and moves faster, the inertia from its mass and the load at the end increases the resistance the motor must overcome. If the stepper motor’s running torque isn’t sufficient at those higher speeds, the arm could stall mid-motion, skip steps or lose its positional accuracy, especially during fast or sudden movements.
STEP ANGLE Another consideration is step angle. A smaller step angle allows for finer control of position, which is preferable for applications that require precise positioning, such as robotic joints, optical systems or 3D printers. The number of steps is also worth determining, as more steps per revolution translates to
36 DESIGN SOLUTIONS MAY 2025
smoother movement, especially at low speeds. This is important in applications like camera sliders, surgical tools or lab automation where jerky motion would directly impact quality and safety. Some modern stepper motors drivers can subdivide full steps into much smaller micro- steps for even greater resolution and smoother operation. However, this can impact torque so needs consideration if stability isn’t a priority.
SIZE AND FORM FACTOR Choosing the wrong motor size can lead to excessive weight or space usage. In addition, a motor that’s too small may struggle to deliver the
necessary torque, while one that’s too large could impact the efficiency of the entire drive system. Form factor doesn’t, however, just refer to motor size. Other additions such as shaft type, mounting pattern and the way the motor is connected to the control system may also require consideration when working with a unique or limited amount of space. While size, torque and step angle are key,
they’re part of a broader decision-making process. Other factors such as power consumption, thermal performance, environmental conditions, cost and compatibility with other drive electronics also play a vital role. For this reason, it’s recommended to consult with an experienced motor supplier, who can assess the application’s unique demands and guide you toward the most suitable motor configuration.
EMS
T: 0118 981 7391
www.ems-limited.co.uk
MULTI-AXIS MOTION CONTROLLER NOW AVAILABLE IN PCB MODULE FORMAT
maxon’s MicroMACS6 multi-axis motion controller is now available in a PCB module format for integration with custom-designed motherboards. The MicroMACS6 Module is an ultra-compact, six-axis motion controller designed for integration into robots and machines. Smaller and lighter than the MicroMACS6, launched
last year, the board is easily mounted to its host with a pair of M2 screws. The MicroMACS6 Module is a master motion controller designed for Delta, SCARA, and mobile robots. The board can also coordinate machines reliant on kinematics, such as pick-and-place applications. Integrating with DC or brushless DC (BLDC) motor controllers to modulate position, speed, and current, the MicroMACS6 Module can achieve multi-axis coordination as a kinematics group, or it can control axes individually. The master controller features a range of motion functions, such as path generator with sinusoidal/trapezoidal profiles, position and velocity control feed forward, as well as position marker/touch probe. The control board features flexible integration with its host, including six digital inputs and two
analogue inputs, all of which are free programmable. It also hosts four digital outputs with free programmable functionality, including a 25kHz PWM capability. For network integration and peripheral device connectivity, the MicroMACS6 Module supports
CANopen, complying with CiA 301 CANopen application layer and CiA 402 motion control profiles, as well as compatibility with EtherCAT. The module also supports Bluetooth Low Energy. Application development is assisted with an extensive software development kit. Of further benefit, the motion controller is suitable for use in demanding environments, with the module capable of operating in temperatures ranging from -30˚C to 55˚C, and humidity up to 90%.
maxon UK & Ireland
www.maxongroup.com/en-gb
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56
