Comprehensive Guide to Actuators Examples: A Hands-on Playbook for Science Students

Actuators are devices that convert various forms of energy, such as electrical, hydraulic, or pneumatic, into mechanical force to achieve physical movements. They are essential components in a wide range of machines, from simple electronic systems to complex industrial devices and robots. This comprehensive guide will provide a detailed exploration of different actuators examples, their technical specifications, and DIY information to help science students gain a deeper understanding of these crucial components.

Electric Linear Actuators

Electric linear actuators use electric motors to produce linear motion. They are known for their high precision, accuracy, and repeatability, making them suitable for a variety of applications, including industrial automation, robotics, and medical devices. The performance metrics of electric linear actuators include:

1. Force Capacity: The maximum force that the actuator can exert. For example, the Progressive Automations PA-14 Linear Actuator has a force capacity of 1400N.
2. Speed: The linear velocity of the actuator’s movement. The PA-14 Linear Actuator has a speed of 10mm/s.
3. Stroke Length: The maximum distance the actuator can travel. The PA-14 Linear Actuator has a stroke length of 50mm.
4. Duty Cycle: The ratio of the time the actuator is active to the total cycle time. The PA-14 Linear Actuator has a duty cycle of 50%.

The high performance of electric linear actuators is achieved through the use of advanced motor technologies, such as brushless DC (BLDC) motors or stepper motors, combined with precision lead screws or ball screws. These actuators are often controlled using microcontrollers or programmable logic controllers (PLCs) to achieve the desired motion profiles.

Hydraulic Linear Actuators

Hydraulic linear actuators use hydraulic fluid to produce linear motion. They are known for their high force capacity, making them suitable for heavy-duty applications in industries such as construction, mining, and manufacturing. The performance metrics of hydraulic linear actuators include:

1. Force Capacity: The maximum force that the actuator can exert. For example, the Parker Hannifin P1F Series Linear Actuator has a force capacity of 100,000lbf (445kN).
2. Speed: The linear velocity of the actuator’s movement. The P1F Series Linear Actuator has a speed of 1.2ips (30.5mm/s).
3. Stroke Length: The maximum distance the actuator can travel. The P1F Series Linear Actuator has a stroke length of 24in (610mm).
4. Pressure Rating: The maximum operating pressure of the hydraulic fluid. The P1F Series Linear Actuator has a pressure rating of 3000psi (20.7MPa).

Hydraulic linear actuators typically use a hydraulic cylinder, which consists of a piston and a cylinder filled with hydraulic fluid. The fluid is pressurized by a hydraulic pump, and the resulting force is transmitted to the piston, causing it to move linearly. These actuators are often used in heavy machinery, construction equipment, and industrial automation systems.

Pneumatic Linear Actuators

Pneumatic linear actuators use compressed air to produce linear motion. They are known for their lightweight, compact design, and ease of maintenance, making them suitable for a wide range of applications, including automation, robotics, and medical devices. The performance metrics of pneumatic linear actuators include:

1. Force Capacity: The maximum force that the actuator can exert. For example, the Festo DPT-Z Series Linear Actuator has a force capacity of 400N.
2. Speed: The linear velocity of the actuator’s movement. The DPT-Z Series Linear Actuator has a speed of 0.5m/s.
3. Stroke Length: The maximum distance the actuator can travel. The DPT-Z Series Linear Actuator has a stroke length of 500mm.
4. Air Pressure Rating: The maximum operating pressure of the compressed air. The DPT-Z Series Linear Actuator has an air pressure rating of 6bar (0.6MPa).

Pneumatic linear actuators typically use a pneumatic cylinder, which consists of a piston and a cylinder filled with compressed air. The air pressure is controlled by a pneumatic valve, and the resulting force is transmitted to the piston, causing it to move linearly. These actuators are often used in automation systems, packaging machinery, and medical equipment due to their simplicity, reliability, and low maintenance requirements.

Piezoelectric Linear Actuators

Piezoelectric actuators use the piezoelectric effect to produce linear or rotary motion. They are known for their high precision, accuracy, and resolution, making them suitable for applications in precision engineering, micro-manipulation, and scientific instruments. The performance metrics of piezoelectric linear actuators include:

1. Displacement: The maximum linear displacement that the actuator can achieve. For example, the Physik Instrumente P-625.1CD Piezo Linear Actuator has a displacement of 25µm.
2. Force Capacity: The maximum force that the actuator can exert. The P-625.1CD Piezo Linear Actuator has a force capacity of 50N.
3. Resonant Frequency: The frequency at which the actuator’s mechanical system oscillates. The P-625.1CD Piezo Linear Actuator has a resonant frequency of 1.5kHz.
4. Blocking Force: The maximum force that the actuator can exert without moving. The P-625.1CD Piezo Linear Actuator has a blocking force of 200N.

Piezoelectric linear actuators use piezoelectric materials, such as lead zirconate titanate (PZT) ceramics, to convert electrical energy into mechanical displacement. When an electric field is applied to these materials, they undergo a small but precise change in their dimensions, which can be used to generate linear motion. These actuators are often controlled using high-voltage amplifiers and specialized control electronics.

Piezoelectric Rotary Actuators

Piezoelectric rotary actuators also use the piezoelectric effect to produce rotary motion. They are known for their high angular resolution, fast response time, and low power consumption, making them suitable for applications in precision positioning, micro-robotics, and scientific instrumentation. The performance metrics of piezoelectric rotary actuators include:

1. Angular Displacement: The maximum angular rotation that the actuator can achieve. For example, the Nanomotion HPS Series Piezo Rotary Actuator has an angular displacement of 180°.
2. Torque Capacity: The maximum torque that the actuator can exert. The HPS Series Piezo Rotary Actuator has a torque capacity of 0.02Nm.
3. Resonant Frequency: The frequency at which the actuator’s mechanical system oscillates. The HPS Series Piezo Rotary Actuator has a resonant frequency of 1kHz.
4. Holding Torque: The maximum torque that the actuator can hold without moving. The HPS Series Piezo Rotary Actuator has a holding torque of 0.1Nm.

Piezoelectric rotary actuators use a combination of piezoelectric materials and mechanical components, such as stators and rotors, to convert electrical energy into rotary motion. These actuators are often used in applications that require high-precision positioning, such as in microscopes, nanopositioning stages, and robotic manipulators.

DIY Actuators

Building your own actuators can be a rewarding and educational experience for science students. Here are some DIY information for the actuators discussed in this guide:

DIY Linear Actuators

To build a simple linear actuator, you can use a DC motor, a lead screw, and a microcontroller. The DC motor provides the rotational motion, which is then converted into linear motion through the lead screw. The microcontroller can be used to control the speed, direction, and position of the actuator. Open-source platforms like Arduino and Raspberry Pi can be used to program and control the actuator.

DIY Piezoelectric Actuators

Building a piezoelectric actuator requires knowledge of materials science, electronics, and programming. You can create a simple piezoelectric actuator using a piezoelectric ceramic, a stainless steel shim, and a voltage amplifier. The piezoelectric ceramic will expand and contract when a voltage is applied, causing the stainless steel shim to bend and produce linear or rotary motion. Again, open-source platforms like Arduino and Raspberry Pi can be used to control the actuator.

By understanding the technical specifications and DIY information for various actuators, science students can gain valuable hands-on experience in designing, building, and testing these essential components. This knowledge can be applied in a wide range of fields, from robotics and automation to scientific instrumentation and medical devices.

References

1. Xu Zhi Huang Hu Dong Jingshi, “A stick-slip piezoelectric actuator with measurable contact force,” Mechatronics, Volume 68, 2020.
2. “A stick-slip piezoelectric actuator with measurable contact force,” ResearchGate, 2020.
3. “Actuators: what is it, definition, types and how does it work,” Progressive Automations, 2022.
4. “Performance Metrics for Fluidic Soft Robot Rotational Actuators,” NCBI, 2021.
5. “Measuring the Performance Criteria of Actuators,” AZoSensors, 2019.