Tokyu Construction and Ishizaka Sangyo begin trial implementation of robot that automatically sorts construction waste – Joint development of “waste sorting robot” that can be introduced into existing intermediate treatment plants –

Tokyu Construction Co., Ltd.
Ishizaka Sangyo Co., Ltd.

Tokyu Construction Co., Ltd. (President: Mitsuhiro Terada) and Ishizaka Sangyo Co., Ltd. (President: Noriko Ishizaka) have jointly developed a “waste sorting robot” that automatically sorts construction waste at intermediate processing plants for construction by-products.

The waste sorting robot can also be installed on the manual sorting line of existing intermediate treatment plants, and is currently being introduced on a trial basis at Ishizaka Sangyo’s plant. Going forward, we will continue to make improvements based on data obtained from the actual line, and will continue development with the aim of putting the robot into practical use with a two-robot system by spring 2021.

By working together, Tokyu Construction, a construction waste generator, and Ishizaka Sangyo, an intermediate processing company, will be able to advance development more efficiently, improve working conditions, and aim to realize a resource-circulating society.

waste sorting robot

At intermediate treatment plants, waste is recycled by sorting and separating materials using wind power and differences in specific gravity, but automation can be difficult depending on the type of waste. Automating the sorting of mixed construction waste, which is a mixture of various materials, is particularly difficult, and it is common for waste flowing on a conveyor belt to be sorted by hand. The waste sorting robot used in this trial implementation is based on the waste sorting technology that Tokyu Construction has researched and developed to date, and uses image analysis technology based on deep learning to automate the sorting process.

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■ Issues facing construction waste

In the construction industry, waste generated at construction sites and other locations is separated and disposed of in accordance with the “Act on Recycling, etc. of Materials Related to Construction Work” (Construction Recycling Act), which was enacted in 2000. However, mixed waste that is difficult to separate is transported to an intermediate treatment plant, where it is separated and classified before being properly disposed of and recycled.

At intermediate treatment plants, mixed construction waste that flows on a conveyor belt is generally roughly sorted by hand, and the work of closely monitoring the waste for long periods of time in a dusty environment is extremely tough, so improving the working environment and a shortage of workers are issues for intermediate treatment companies.In addition, the shortage of workers is leading to a stagnation in the recycling of construction by-products and rising waste treatment costs, and is expected to become a future issue for waste-generating companies as well.

■ History of joint development

Tokyu Construction has been researching and developing construction waste sorting robots for demolition sites since 2006, and has accumulated a wealth of data and know-how. Furthermore, looking ahead to 2030, the company sees the United Nations’ Sustainable Development Goals (SDGs) as a business opportunity, and has declared that it will develop unique initiatives based on the three values ​​it aims to provide: decarbonization, zero waste, and disaster prevention and mitigation.

Ishizaka Sangyo is a company that carries out intermediate treatment of industrial waste in its environmentally friendly, all-weather independent plants, with a vision of “Zero Waste Design (aiming for a society where all waste is turned into resources).” It is a leading company in Japan in dry separation and classification technology for construction waste, boasting a reduction and recycling rate of 98%, and is actively engaged in research and development with the aim of achieving a 100% recycling rate.

The two companies share a common understanding of the challenges of construction waste and believe that by sharing and utilizing each other’s knowledge and know-how, they can expect to achieve more efficient and effective results, and have therefore embarked on this joint development.

Details of the “Waste Sorting Robot”

• Mixed construction waste is continuously transported on a conveyor belt and photographed with a camera. The type and location of the waste are identified using deep learning analysis technology from color and range images, and only the targeted items are picked up by a robotic arm and collected into a box.
• Because it can distinguish the top layer of waste from overlapping (multi-layered) waste, it can be sorted without dividing the waste into a sparse single layer with gaps, and can be installed on existing conveying lines.
• In addition, since the robot can handle belt conveyor speeds of up to 40 meters per minute, it is possible to minimize the decline in processing capacity due to the introduction of the robot and prevent it from affecting other processing processes.

Pilot details

• At the sorting line within Ishizaka Sangyo’s all-weather independent comprehensive plant, a waste sorting robot will be used to separate wood from mixed construction waste, and the sorting accuracy and durability will be verified.
• The goal is to achieve a picking speed of 2,500 items per hour with two robots by the end of fiscal year 2020.
• We aim to use additional learning functions for deep learning to improve the system so that it can adapt to the changing waste situation on a daily basis.