SoftBank Group Corp on Wednesday said it has agreed to buy the robotics business of Swiss engineering group ABB in a US$5.4 billion deal.The deal marks a major push by SoftBank founder and CEO Masayoshi Son into robotics, as he expands investment activity after a period of retrenchment.SoftBank, whose forays into robotics include the humanoid Pepper, has investments in the segment, including in Berkshire Grey and AutoStore.The deal means ABB has abandoned its original decision to spin off and...