Design and Implementation of a Mechatronic System

Study Case Design and Implementation of a Mechatronic System in a Hybrid Energy-Based Lawn Mower Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract This study aims to apply mechatronic technology to a hybrid energy-based lawn mower. Tests were conducted on the power source, transmission system performance, and energy consumption comparison between this designed machine and a conventional lawn mower. The machine design utilizes a 12-volt battery with a capacity of 7.2 Ah and a wireless control system operating at a frequency of 315 MHz. The actuator system consists of three main components: a cutting motor, a transmission drive motor, and a servo motor. The battery charging process is carried out using a hybrid system, which is a combination of a 10 Wp solar panel and a 72 Watt electric charger. The machine can operate between 50 and 75 minutes for each full charging cycle, depending on the power load. Test results show that the fastest cutting time occurs at a grass height of 20 mm, which is 6 minutes and 15 seconds, while the longest time occurs at a grass height of 60 mm, which is 11 minutes and 30 seconds. The battery charging process using solar panels takes between 6 hours and 42 minutes to 11 hours and 43 minutes, while charging using a standard household electric charger (AC 110V) takes 1 hour and 12 minutes. A cost evaluation shows that operational efficiency increases by up to $59 per month compared to conventional machines with the same test parameters. Keywords: Hybrid system, power efficiency, operating time, conventional machine. INTRODUCTION Every device that has a mechanical and electrical system requires an energy source as a major component in its operation. Generally, energy sources are classified into three types: renewable energy, non-renewable energy, and non-depletable energy, each MICHAEL KURNIAWAN 1 Study Case with different characteristics and applications. According to Bakar (2014), the application of mechatronics technology has expanded in various fields, particularly in automated devices such as industrial robots, CNC machines, 3D printers, and other smart manufacturing systems. The use of this technology allows for higher work efficiency compared to conventional systems. For example, conventional lathes require high precision and working time, while CNC (Computer Numerical Control) lathes can operate automatically using command codes without direct operator intervention. In 2016, Andika Suryadi, an engineering student from Malang, designed a mechatronics-based lawn mower prototype that uses fossil fuels as its main energy source. Although it uses an ATmega8 microcontroller and a wireless control system, the machine still has the disadvantage of relying on non-renewable fossil fuels. Based on an evaluation of the previous system, this study designed a more efficient and environmentally friendly mechatronic lawn mower through the application of a hybrid energy system. This technology combines electrical power from the power grid with energy from solar panels to achieve better energy efficiency and sustainability. The main objectives of this study are: 1. To determine the working duration of a mechatronic-based lawn mower based on the area and grass height. 2. To compare the performance and energy efficiency with a conventional gasoline-powered machine. 3. To analyze the battery charging time using a hybrid system and power consumption during the mowing process. The mechatronics system in this design includes the integration of mechanics, electronics, control systems, automation, and control motors. With this synergy, it is hoped that this design can overcome various limitations found in previous generations of lawn mowers. MICHAEL KURNIAWAN 2 Study Case MECHATRONICS SYSTEM STRUCTURE Mechatronics systems cover two main areas: mechanics and electronics. The main elements in this system include: 1. Machine Mechanisms Mechanically controlled components, such as robot arms, vehicle transmission systems, or generators. 2. Sensors Function to detect physical conditions and convert them into electrical signals that can be processed. 3. Controller Processes data from sensors and determines system actions to match desired reference values. In the context of this lawn mower, the control system receives commands from the operator via a wireless transmitter and receiver module, enabling control of forward, reverse, turning, and stopping movements. The receiver is installed on the mechanical unit to activate the actuator, while the transmitter is held by the user (operator). The control module used supports multiple channels, depending on the system requirements (Instrument, 2016). HYBRID ENERGY SYSTEM TECHNOLOGY Hybrid energy systems combine two main sources of power: electrical energy from the national grid and solar energy. As the engine operates, the battery capacity will decrease over time. The system is designed so that the solar panels automatically supply additional power when the battery level drops, and stop charging once maximum capacity is reached. Figure 1. Schematic Diagram of Hybrid Energy System Operation MICHAEL KURNIAWAN 3 Study Case CALCULATION METHOD Solar Panel Planning The number of solar panels is determined based on daily energy requirements using the equation: 𝑛= 𝐸𝑡 𝐸𝑠 If the charging process takes more than one hour per day, the time (T) is included in the calculation: 𝑛= 𝐸𝑡 𝐸𝑠 × 𝑇 Electric Charging Process The duration of electric charging is determined by the equation: 𝑇𝑎 = 𝐶 𝐼𝑐 where C= battery capacity (Ah), and I_c= charging current (A). Battery Efficiency The effective working time of the battery is calculated by: 𝑇𝑤 = 𝐶×𝑉 𝑃×𝜂 Meanwhile, the battery output current is obtained from: 𝐼𝑎 = 𝑃 𝑉 Energy Consumption A comparison of energy consumption is made between fossil fuel (gasoline) engines and battery-based electric engines. The cost of electrical energy is calculated using the equation: 𝐵ℎ = 𝑃 × 𝑡 × 𝐶𝑒 where: B_h= energy cost ($), P= power (W), t= operating time (hours), C_e= electricity rate per kWh (referring to the U.S. Energy Information Administration rate) MICHAEL KURNIAWAN 4 Study Case RESEARCH METHOD To achieve the research objectives, the main specifications of the lawn mower to be designed were first determined. The machine frame uses carbon steel with a total mass of 8 kg and is equipped with off-road tires, which significantly affect motor performance. The amount of power used by the machine will depend on the load level received by the motor during operation. Control System Design In the initial design stage, the control system used a frequency of 27 MHz, a common frequency found in radio-controlled toy cars. However, during the first test, the system failed to operate due to overheating of the receiver mainboard. This condition was caused by the receiver's inability to withstand the high load current from the transmission motor. To overcome this, the control system's operating frequency was changed to 315 MHz, which is more stable and commonly used in medium-power wireless systems such as garage door controllers or drone transmitters. Figure 2. 315 MHz RF Remote Control Charger Controller Settings To optimize the performance of the solar panel in charging the 12-volt battery, the charger controller was set according to the Standard Operating Procedure (SOP). The device interface is shown in Figure 3. Figure 3. Charger Controller Interface MICHAEL KURNIAWAN 5 Study Case The standard setup procedure is as follows: 1. Connect the charger controller to the 12-volt battery. 2. Connect the solar panel to the charger controller. 3. Press the Menu button several times until the parameter you want to change appears. 4. Press and hold the Menu button for ±3 seconds until the screen flashes. 5. Use the (+) or (–) buttons to adjust the parameter value as needed. 6. When finished, press Menu once more to save and exit setup mode. Figure 4. Charger Controller Default Standard Settings Transmission System The initial transmission system uses a pulley and V-belt mechanism, as shown in Figure 5. Figure 5. Lawn Mower with Pulley and V-belt Transmission System Component Specifications: 1. Drive pulley 1.5 inches (3.81 cm) 2. Driven pulley 3 inches (7.62 cm) 3. V-belt Type A-28 4. Distance between shafts 5. Motor speed 240 rpm 6. Output shaft speed MICHAEL KURNIAWAN 20 mm 120 rpm 6 Study Case RESULTS AND DISCUSSION To determine the torque of the cutting motor, the electrical power consumed during machine operation was first calculated. Testing was conducted at three different grass heights. Each test used the same cutting area and battery capacity. During testing, the output current was measured using a panel interface ammeter, with 30 data samples taken randomly at intervals of approximately 5 meters. The highest current value was taken when the motor performed a jump start. The data was then converted into a graph comparing the power between the different cutting heights. Figure 6. Power Comparison Graph at Various Cutting Heights From Figure 6, it can be seen that the highest power surge occurred when the engine started operating (initial start). This surge was caused by the large amount of energy required to rotate the cutting blades from a stationary position. In subsequent tests, the highest power consumption occurred when cutting grass with a height of 20 mm, because the denser grass structure near the ground surface requires greater cutting torque. The higher the power requirement, the higher the torque produced by the motor, in accordance with the linear relationship between power (P) and torque (T). Battery Charging Process The parameters observed include full charging time, charger input power, and battery capacity. In the hybrid charging system, the maximum input current recorded was 5.9 A, which then gradually decreased to 0 A. The voltage increased from 10.44 V to 14.44 V when the battery reached full capacity. MICHAEL KURNIAWAN 7 Study Case Figure 7. Voltage Increase Graph During the Battery Charging Process The graph shows a steady increase in voltage until it peaks at 14.4 V, indicating that the battery is fully charged. Figure 8. Current Decrease Graph During the Battery Charging Process The current graph shows a downward trend until it reaches 0 A, because the internal resistance of the battery increases as it approaches a full charge. Unlike charging via solar panels, charging with electricity from the power grid (U.S. Power Grid) does not depend on weather conditions or time. This type of charging utilizes 110V AC power from the household electrical network, making the process more stable and faster. Meanwhile, charging using a 10 Wp (12 V) solar panel shows significant variations in power output due to changes in sunlight intensity throughout the day. Voltage and current data were observed using a voltmeter and ammeter. MICHAEL KURNIAWAN 8 Study Case Figure 9. Comparison Chart of Battery Charging Using Solar Panels The chart above shows that the power output of solar panels is not constant. Observations over five days showed fluctuations in power supply; on days 3 and 4, the solar panel did not generate power until 11:00 AM due to cloudy conditions. The highest output was achieved on day 5 at 1:00–2:00 PM, with a voltage of 17.65 V, a current of 1.21 A, and a total power of 21.35 W. CONCLUSION Based on the results of research on the design of a mechatronic system in a hybrid energy-based lawn mower, the following conclusions were obtained: 1. Motor torque: a. The transmission motor produces a torque of 2.42 N·m. b. The cutting motor produces a maximum torque of 0.26 N·m. c. The fastest cutting time at a grass height of 20 mm is 6 minutes 15 seconds, while the longest time at a height of 60 mm reaches 11 minutes 30 seconds. 2. Battery charging time: a. With the solar panel, the longest charging time occurs on the 4th day for 11 hours 43 minutes, and the fastest time on the 5th day for 6 hours 42 minutes. b. With a grid charger (AC 110V), the full charging time is only 1 hour 12 minutes. 3. Power consumption: a. The highest power consumption during grass cutting at a height of 20 mm was 81.72 W. b. The lowest power consumption at a height of 60 mm was 54.96 W. These results indicate that the hybrid system provides high efficiency, energy source flexibility, and stable, environmentally friendly mechatronic performance for residential lawn care applications in the United States. MICHAEL KURNIAWAN 9 Study Case REFERENCE MICHAEL KURNIAWAN 10