Mechatronics, Control Engineering, Actuators and Parallel Robots
Modern robotics combines mechanics, electronics, sensors, software, actuators, and control systems. Hexapods and Stewart platforms are a particularly useful example because six actuators must work together as one coordinated positioning system.
What Is Mechatronics?
Mechatronics is the integration of mechanical engineering, electronics, computer control, sensors, actuators, and software into a complete machine or motion system. Rather than treating a mechanism, motor, controller, and software as separate items, mechatronics engineering considers how all of them interact.
A mechatronics engineer may work on robotic manipulators, precision positioning stages, mobile robotics, automated test equipment, machine tools, laboratory automation, or complex multi-axis motion systems.
Typical Mechatronics Components
- Mechanical structures, bearings, linkages, and guides
- Actuators such as electric motors, piezo actuators, voice coils, and linear drives
- Position, force, optical, inertial, and other sensors
- Motion controllers and microcontrollers
- Power electronics and servo drives
- Real-time control software and user interfaces
In a mechatronics laboratory, students and engineers often work with robotics components, motor drives, sensors, control software, embedded controllers, and mechanical test setups. Common educational systems include inverted pendulums, acrobots, serial robot arms, delta robots, and other mechanisms that make dynamic behavior and feedback control easy to observe.
Control Systems Engineering
Control engineering, also called controls engineering or control systems engineering, is the discipline of making a system behave in a desired way. A control engineer uses measurements from sensors, compares them with a target value, and commands actuators to reduce the difference.
A basic position control loop, for example, measures the actual position of a stage or robot, compares it with the commanded position, and continuously adjusts motor force or torque. More advanced engineering control systems coordinate multiple axes, compensate for disturbances, optimize settling time, and protect the machine from unsafe operating conditions.
What Is a Control System?
A control system is a combination of hardware and software that regulates the behavior of a machine or process. It can be open-loop, where commands are issued without measuring the result, or closed-loop, where sensor feedback is continuously used to correct the motion.
Modern systems and control engineering often combines feedback control, trajectory generation, filtering, kinematic transformations, motion planning, safety logic, and communication with higher-level automation systems.
| Control Element | Function | Robotics Example |
|---|---|---|
| Setpoint | Defines the desired state. | Target position or angle. |
| Sensor | Measures the actual state. | Encoder, force sensor, camera, or interferometer. |
| Controller | Calculates the required correction. | Servo controller or real-time motion controller. |
| Actuator | Produces physical motion or force. | Motor, piezo actuator, voice coil, or pneumatic cylinder. |
| Mechanism | Transfers motion to the load. | Robot arm, delta mechanism, linear stage, or hexapod. |
An actuator converts electrical, pneumatic, hydraulic, thermal, or other input energy into physical motion or force. In robotics, actuators are the elements that actually move joints, stages, grippers, platforms, wheels, or other mechanisms.
Rotary Actuators
DC motors, brushless motors, stepper motors, and torque motors commonly drive rotary robot joints, wheels, and rotary stages.
Linear Actuators
Lead screws, ball screws, linear motors, voice coils, and piezoelectric drives create controlled linear motion.
Specialized Actuators
Piezo actuators provide extremely fine motion, while pneumatic and hydraulic actuators are useful where high force or specific environmental characteristics are required.
What are actuators used for? They generate the controlled motion required to position a robot or payload. In a hexapod, six linear actuators change length in a coordinated way to generate motion in X, Y, Z, pitch, yaw, and roll.
The choice of actuator affects speed, force, travel range, resolution, stiffness, heat generation, efficiency, and control behavior. For precision robotics, the actuator cannot be considered in isolation. The sensor, mechanics, drive electronics, control algorithm, and load all influence final system performance.
Serial Robot
A serial robot connects joints one after another in a kinematic chain. Conventional industrial robotic arms are common examples. Serial robots can provide a large workspace, but errors and compliance from individual joints can accumulate along the chain.
Delta Robot
A delta robot is a parallel robot that typically uses three articulated arms connected to a common moving platform. Delta robot arms are widely associated with fast pick-and-place motion because the moving parts can be kept relatively light.
Parallel Manipulator
A parallel manipulator supports and moves one platform using multiple kinematic chains at the same time. Stewart platforms and many hexapods are parallel manipulators.
There are many types of manipulators in robotics. A robotic manipulator arm may have four, six, or more degrees of freedom, depending on the task. A 4-axis robot might control three translations and one rotation, while a 6-axis system can control all three translations and all three rotations.
Mobile manipulation combines a movable robot base with a manipulator, allowing the machine to travel through an environment and then physically interact with objects. This is different from a fixed robotic manipulator, but both depend on coordinated actuators, sensors, control systems, and software.
Hexapod Definition
In precision positioning, a hexapod is a six-degree-of-freedom parallel-kinematic mechanism. Six independently controlled actuators connect a fixed base to a movable platform. Coordinating the actuator lengths moves the platform in X, Y, Z, pitch, yaw, and roll.
The term Stewart platform is commonly used for this class of six-actuator parallel mechanism. The name Stewart-Gough platform is also widely used. Misspellings such as "Stuart platform" appear in searches, but Stewart platform is the standard term. Learn how hexapods differ from conventional 6-axis robots.
Why Use Parallel Kinematics?
- Six-axis motion from one compact mechanism
- All actuators act directly on one moving platform
- High structural stiffness can be achieved
- No stacked accumulation of separate X, Y, Z and rotary stages
- Software can transform Cartesian motion commands into individual actuator movements
- A virtual pivot point can be useful for aligning optics and other payloads
Hexapod robots are used when a payload must be positioned precisely in several axes at once. Applications include optics alignment, photonics, metrology, semiconductor equipment, aerospace test systems, microscopy, and scientific instrumentation.
Standard HexapodsMiniature HexapodsVacuum HexapodsHigh-Load Hexapods
A robotics laboratory brings together mechanics, actuators, electronics, sensors, control hardware, and software so that complete systems can be designed and tested. Depending on the purpose of the robotic lab, equipment may range from small educational platforms to high-precision research systems.
Typical Robotics Lab Equipment
- Robot manipulators and robotic arms
- Linear and rotary positioning stages
- Hexapods and parallel robots
- Delta robots
- Mobile robotics platforms
- Motor drives and power actuators
- Encoders and other sensors
- Microcontrollers and real-time control hardware
Control Experiments
- Inverted pendulum stabilization
- Acrobot control
- Position and velocity servo tuning
- Trajectory following
- Multi-axis synchronization
- System identification
- Disturbance rejection
- Repeatability and accuracy testing
Laboratory robotics is especially valuable because it allows engineers to compare mathematical models with physical behavior. Friction, backlash, structural compliance, vibration, sensor noise, delays, and actuator limits can all affect a real machine even when the theoretical model appears straightforward.
Experiments and performance tests are important because they allow a proposed improvement, explanation, design, or control method to be tested against measured results. Repeated trials help determine whether an observed result is consistent or whether it may have been caused by random variation, measurement noise, changing environmental conditions, or an uncontrolled variable.
Why Do Engineers Repeat Experiments?
Engineers and scientists repeat experiments to determine whether the result can be obtained consistently. A single successful test may be interesting, but repeated measurements provide much stronger evidence that the result reflects the system being studied.
Repeatability in Robotics
For a motion system, repeatability describes how consistently it returns to the same position under defined conditions. Repeated trials can reveal random positioning error, thermal drift, mechanical hysteresis, control instability, or load-dependent effects.
Repeatability is not the same as accuracy. A robot can return very consistently to the same location while that location is offset from the commanded position. For that reason, precision motion experiments often evaluate accuracy, repeatability, resolution, stability, settling behavior, and other performance characteristics separately.
What is a mechatronics engineer?
A mechatronics engineer designs systems that combine mechanical components, electronics, sensors, actuators, embedded computing, and control software.
What is controls engineering?
Controls engineering focuses on regulating the behavior of machines and processes. In robotics, that often means using sensor feedback and control algorithms to command actuators and achieve the desired motion.
What is a control engineer?
A control engineer develops and tunes the hardware and algorithms that govern system behavior, including servo loops, motion trajectories, synchronization, filtering, safety functions, and system response.
What is control system engineering?
Control system engineering is the analysis and design of systems that use inputs, feedback, algorithms, and actuators to produce predictable behavior. It is central to robotics, automation, aerospace, manufacturing, and precision motion.
What is an actuator in robotics?
An actuator is the component that generates movement or force. Motors, linear drives, piezo actuators, voice coils, and fluid-power cylinders are all examples.
What is a Stewart platform?
A Stewart platform is a parallel mechanism in which six actuators connect a base to a moving platform. In precision motion applications, this arrangement is commonly called a hexapod and provides six degrees of freedom.
What is a delta robot?
A delta robot is a parallel robot with multiple arms connecting a fixed base to a moving platform. Its low moving mass can support very fast motion, especially in pick-and-place applications.
Why is it important to repeat experiments?
Repeating an experiment helps determine whether the result is consistent and reproducible rather than the product of random variation or an uncontrolled condition.
Hexapods bring together many of the core topics of mechatronics and control engineering: actuators, sensors, mechanics, kinematics, servo control, coordinate transformation, and multi-axis synchronization.
Hexapod PositionersHexapod Control and SoftwareSpecial Hexapods